Annual report pursuant to Section 13 and 15(d)

Property Portfolio (Schedule of Recognized Identified Assets Acquired and Liabilities Assumed) (Details)

v3.8.0.1
Property Portfolio (Schedule of Recognized Identified Assets Acquired and Liabilities Assumed) (Details)
$ in Thousands
Dec. 31, 2017
USD ($)
Lewisburg facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest $ 7,300
Lewisburg facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 681
Lewisburg facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 6,114
Lewisburg facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 373
Lewisburg facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 132
Clermont Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 5,225
Clermont Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 145
Clermont Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 4,422
Clermont Facility [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 488
Clermont Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 255
Clermont Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 125
Clermont Facility [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment (210)
Oklahoma City Facilities [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 49,500
Oklahoma City Facilities [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 2,953
Oklahoma City Facilities [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 38,724
Oklahoma City Facilities [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 759
Oklahoma City Facilities [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 4,392
Oklahoma City Facilities [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 2,672
Brockport Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 8,670
Brockport Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 693
Brockport Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 7,097
Brockport Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 841
Brockport Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 454
Brockport Facility [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment (415)
Flower Mound Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 4,050
Flower Mound Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 730
Flower Mound Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 3,155
Flower Mound Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 222
Flower Mound Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 185
Flower Mound Facility [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment (242)
Lubbock Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 8,200
Lubbock Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 1,567
Lubbock Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 5,725
Lubbock Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 414
Lubbock Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 494
Germantown Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 15,940
Germantown Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 3,050
Germantown Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 8,385
Germantown Facility [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 3,284
Germantown Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 587
Germantown Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 634
Austin Facility [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 40,650
Austin Facility [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 7,223
Austin Facility [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 29,616
Austin Facility [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 246
Austin Facility [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 1,680
Austin Facility [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 1,885
Fort Worth [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 6,250
Fort Worth [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 1,738
Fort Worth [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 3,726
Fort Worth [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 126
Fort Worth [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 314
Fort Worth [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 346
Albertville [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 6,800
Albertville [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 1,154
Albertville [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 4,444
Albertville [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 103
Albertville [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 802
Albertville [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 297
Moline [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 11,900
Moline [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 854
Moline [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 9,237
Moline [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 33
Moline [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 1,050
Moline [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 833
Moline [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment (107)
Lee’s Summit [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 3,800
Lee’s Summit [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 571
Lee’s Summit [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 2,929
Lee’s Summit [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 303
Lee’s Summit [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 134
Lee’s Summit [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets (137)
Ellijay Facilities [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 4,900
Ellijay Facilities [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 913
Ellijay Facilities [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 3,337
Ellijay Facilities [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 672
Ellijay Facilities [Member] | Leasing commissions and legal fees [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 198
Ellijay Facilities [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment (220)
Encompass facilities [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 68,093
Encompass facilities [Member] | Land And Site Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 5,615
Encompass facilities [Member] | Building And Tenant Improvements [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 56,221
Encompass facilities [Member] | Above Market Lease Intangibles [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 74
Encompass facilities [Member] | In Place Leases [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 5,154
Encompass facilities [Member] | Leasing costs [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets 1,088
Encompass facilities [Member] | Below Market Lease Intangible [Member]  
Business Acquisition [Line Items]  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment $ (59)