Annual report pursuant to Section 13 and 15(d)

Financial Statement Schedule (Details)

v3.8.0.1
Financial Statement Schedule (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
Revolving Credit Facility [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances $ 164,900
West Mifflin Note Payable [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances 7,378
Cantor Loan [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances $ 32,097
Minimum [Member] | Building [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 30 years
Minimum [Member] | Tenant Improvement [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 3 years
Minimum [Member] | Site Improvements [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 4 years
Maximum [Member] | Building [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 51 years
Maximum [Member] | Tenant Improvement [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 16 years
Maximum [Member] | Site Improvements [Member]  
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]  
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation 15 years