Real Estate Assets, Discontinued Operations and Assets Held for Sale (Aggregate Balance Sheet of Properties Held for Sale Included in Discontinued Operations) (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021 USD ($) a buildings entities	Dec. 31, 2020 USD ($) buildings	Mar. 31, 2022 buildings	Jul. 27, 2021 buildings	Jul. 22, 2021 a buildings
Held for Sale Assets in Continuing and Discontinued Operations
Continuing Operations, Number of In-service Properties Held for Sale | buildings	23
Continuing Operations, Number of Real Estate Properties Sold | buildings	5	7
Total Properties Sold or Classified as Held for Sale | buildings	35
Number of Real Estate Properties | entities	3
Equity Method Investment, Ownership Percentage	20.00%
Number of Tranches of Contributed Assets | entities	3
Total assets held-for-sale	$ 435,606	$ 67,946
Total liabilities related to assets held-for-sale	$ 23,939	7,740
Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Number of Real Estate Properties | buildings	23
Subsequent Event [Member]
Held for Sale Assets in Continuing and Discontinued Operations
Equity Method Investment, Ownership Percentage				20.00%
Subsequent Event [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Number of Real Estate Properties | buildings					14
Land | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Area of Real Estate Property | a	15.0
Land | Subsequent Event [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Area of Real Estate Property | a					15.0
Major Customer | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Number of Real Estate Properties | buildings	9
Continuing Operations [Member]
Held for Sale Assets in Continuing and Discontinued Operations
Land and improvements	$ 197,287	27,954
Buildings and tenant improvements	325,874	44,800
Construction in progress	25	0
Undeveloped land	1,338	0
Accumulated depreciation	(123,696)	(5,976)
Deferred leasing and other costs, net	18,609	936
Other assets	16,169	232
Total assets held-for-sale	435,606	67,946
Accrued expenses	4,296	660
Other liabilities	19,643	7,080
Total liabilities related to assets held-for-sale	$ 23,939	$ 7,740
Tranche 1 | Major Customer | Subsequent Event [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Number of Real Estate Properties | buildings				3
Tranches 2 and 3 | Major Customer | Subsequent Event [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations
Held for Sale Assets in Continuing and Discontinued Operations
Number of Real Estate Properties | buildings			6