Property Portfolio - (Details)

v3.21.1

Property Portfolio - (Details) $ in Thousands																					3 Months Ended		12 Months Ended
	Jan. 15, 2021 USD ($) lease property	Jan. 12, 2021 USD ($) lease	Dec. 30, 2020 USD ($) item lease property	Dec. 29, 2020 USD ($) tenant property lease	Dec. 14, 2020 USD ($) lease property	Dec. 01, 2020 USD ($) lease property	Nov. 23, 2020 USD ($)	Nov. 18, 2020 USD ($) lease property	Oct. 27, 2020 USD ($) property lease tenant	Oct. 20, 2020 USD ($) property lease tenant	Sep. 30, 2020 USD ($) lease	Sep. 18, 2020 USD ($)	Jul. 31, 2020 USD ($) tenant lease	Jul. 17, 2020 USD ($)	Jul. 16, 2020 USD ($)	Apr. 27, 2020 USD ($)	Mar. 20, 2020 USD ($) lease	Mar. 04, 2020 USD ($)	Feb. 27, 2020 USD ($)	Feb. 13, 2020 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) item
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | item																							18
Depreciation, Total																					$ 7,848	$ 5,836
Tenant Improvement Allowances Receivable																					29,500
Capital Lease Obligations, Noncurrent																					18,900
Property, Plant and Equipment, Additions																					$ 43,570		$ 237,376
Debt Instrument, Term																					2 years 6 months 29 days		2 years 9 months 14 days
Commercial mortgage-backed securities (CMBS)
Property, Plant and Equipment [Line Items]
Debt Instrument, Face Amount																$ 12,100
Debt Instrument, Interest Rate, Stated Percentage																4.68%
Debt Instrument, Term																4 years
Lease Intangibles Asset [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Asset, Useful Life																					5 years 2 months 12 days
Lease Intangibles Liability [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Asset, Useful Life																					4 years 7 months 6 days
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					$ 4,183		$ 33,476
El Paso Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions		$ 10,000																			10,017
Number or leases assumed | lease		3
Lessor, Operating Lease, Term of Contract		4 years
El Paso Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					899
Syracuse Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions	$ 6,200																				6,397
Number or leases assumed | lease	2
Lessor, Operating Lease, Term of Contract	8 years
Syracuse Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					616
West El Paso Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property	2
Property, Plant and Equipment, Additions	$ 9,600																				9,578
Number of new leases entered into | lease	2
Lessor, Operating Lease, Term of Contract	12 years
Leases with tenant renewal options | lease	3
Operating Lease, Weighted Average Remaining Lease Term	7 years
West El Paso Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					851
Fort Worth Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					17,444
Fort Worth Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																					$ 1,817
High Point Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																				$ 25,100			25,081
Lessor, Operating Lease, Term of Contract																				3 years
High Point Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,749
Clinton Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																			$ 11,600				11,619
Lessor, Operating Lease, Term of Contract																			4 years
Clinton Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							664
West Allis Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																		$ 9,100					9,357
Lessor, Operating Lease, Term of Contract																		4 years
West Allis Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							974
Grand Rapids Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																	$ 22,700						22,794
Number or leases assumed | lease																	11
Lessor, Operating Lease, Term of Contract																	5 years
Grand Rapids Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							2,951
Dumfries Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																$ 19,600
Lessor, Operating Lease, Term of Contract																9 years 6 months
Centerville Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions															$ 5,100								5,071
Lessor, Operating Lease, Term of Contract															10 years 6 months
Centerville Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Weighted Average Remaining Lease Term															49 years
Fairfax Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions														$ 17,900									19,745
Lessor, Operating Lease, Term of Contract														9 years 1 month 6 days
Fairfax Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							6,731
Rosedale Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions													$ 23,100										23,891
Debt Instrument, Face Amount													$ 14,800
Debt Instrument, Interest Rate, Stated Percentage													3.85%
Debt Instrument, Term													5 years
Number or leases assumed | lease													8
Number of tenants assumed | tenant													6
Lessor, Operating Lease, Term of Contract													6 years 7 months 6 days
Rosedale Facilities [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							2,856
Lancaster Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions												$ 6,300											6,305
Lessor, Operating Lease, Term of Contract												8 years 6 months
Lancaster Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							696
Winston-Salem Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions											$ 8,500												9,240
Number or leases assumed | lease											5
Lessor, Operating Lease, Term of Contract											4 years
Winston-Salem Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,524
Decatur and Jackson Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property										2
Property, Plant and Equipment, Additions										$ 10,900													10,912
Number or leases assumed | lease										6
Number of tenants assumed | tenant										5
Operating Lease, Weighted Average Remaining Lease Term										6 years
Decatur and Jackson Facility [Member] | Decatur [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property										1
Decatur and Jackson Facility [Member] | Jackson [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property										1
Decatur and Jackson Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							2,237
Sheboygan and Plymouth Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property									2
Property, Plant and Equipment, Additions									$ 13,800														13,824
Number or leases assumed | lease									3
Number of tenants assumed | tenant									2
Operating Lease, Weighted Average Remaining Lease Term									5 years
Sheboygan and Plymouth Facility [Member] | Sheboygan [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property									1
Sheboygan and Plymouth Facility [Member] | Plymouth [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property									1
Sheboygan and Plymouth Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,088
Spring Hill and Hudson Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property								3
Property, Plant and Equipment, Additions								$ 18,200															18,218
Number or leases assumed | lease								3
Lessor, Operating Lease, Term of Contract								8 years
Spring Hill and Hudson Facility [Member] | Spring Hill [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property								2
Spring Hill and Hudson Facility [Member] | Hudson [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property								1
Spring Hill and Hudson Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							3,473
Cape Girardeau Facility [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions							$ 7,400																7,350
Lessor, Operating Lease, Term of Contract							6 years
Cape Girardeau Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,150
Yuma Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property						2
Property, Plant and Equipment, Additions						$ 7,000																	6,979
Number or leases assumed | lease						2
Operating Lease, Weighted Average Remaining Lease Term						4 years
Yuma Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,041
Las Vegas Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property					2
Property, Plant and Equipment, Additions					$ 7,100																		7,124
Number of new leases entered into | lease					2
Lessor, Operating Lease, Term of Contract					12 years
Las Vegas Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							311
Pensacola Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property				3
Property, Plant and Equipment, Additions				$ 9,100																			9,052
Number or leases assumed | lease				3
Number of tenants assumed | tenant				2
Operating Lease, Weighted Average Remaining Lease Term				9 years
Pensacola Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							1,786
Venice Facility [Member]
Property, Plant and Equipment [Line Items]
Number of Properties Acquired | property			2
Property, Plant and Equipment, Additions			$ 7,000																				6,975
Number or leases assumed | lease			2
Lessor, Operating Lease, Term of Contract			5 years 6 months
Leases with tenant renewal options | item			0
Venice Facility [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions																							$ 1,648