Real Estate Properties - Disposition Activities (Details) $ in Thousands		12 Months Ended
	Feb. 14, 2023 USD ($) ft² property	Dec. 31, 2022 USD ($) ft² property	Dec. 31, 2021 USD ($) ft² property parcel_of_land	Dec. 31, 2020 USD ($) ft² property
Real Estate Properties [Line Items]
Number of properties (in properties) | property		160
Rentable square feet (in square feet) | ft²			926,000	163,000
Gain (Loss) on Sale of Real Estate		$ 11,001	$ 78,354	$ 10,855
Loss on impairment of real estate		$ 21,820	$ 62,420	$ 2,954
Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		18	6	10
Rentable square feet (in square feet) | ft²		2,326,000	2,565,000	906,000
Gross Sales Price, Excluding Closing Costs		$ 211,020	$ 226,915	$ 110,463
Gain (Loss) on Sale of Real Estate		11,001	78,354	10,855
Loss on impairment of real estate		$ 21,820	$ 45,196	$ 2,954
Disposal Group, Disposed of by Sale | Subsequent Event
Real Estate Properties [Line Items]
Number of properties (in properties) | property	2
Rentable square feet (in square feet) | ft²	207,000
Gross Sales Price, Excluding Closing Costs	$ 7,600
Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Number of properties (in properties) | property			2
Loss on impairment of real estate			$ 6,991
Rockville, MD | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		129,000
Gross Sales Price, Excluding Closing Costs		$ 6,750
Gain (Loss) on Sale of Real Estate		$ (72)
Chesapeake, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		2
Rentable square feet (in square feet) | ft²		172,000
Gross Sales Price, Excluding Closing Costs		$ 18,945
Gain (Loss) on Sale of Real Estate		$ 2,296
Milwaukee, WI | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		29,000
Gross Sales Price, Excluding Closing Costs		$ 3,775
Gain (Loss) on Sale of Real Estate		$ (75)
Holtsville, NY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		264,000
Gross Sales Price, Excluding Closing Costs		$ 28,500
Gain (Loss) on Sale of Real Estate		$ 1,900
Fairfax, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1		1
Rentable square feet (in square feet) | ft²		184,000		83,000
Gross Sales Price, Excluding Closing Costs		$ 19,750		$ 22,200
Gain (Loss) on Sale of Real Estate		$ (13,537)		4,754
Loss on impairment of real estate				$ 0
Houston, TX | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		206,000
Gross Sales Price, Excluding Closing Costs		$ 9,800
Gain (Loss) on Sale of Real Estate		(135)
Loss on impairment of real estate		$ 15,278
Birmingham, AL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		3
Rentable square feet (in square feet) | ft²		448,000
Gross Sales Price, Excluding Closing Costs		$ 16,050
Gain (Loss) on Sale of Real Estate		(265)
Loss on impairment of real estate		$ 3,709
Erlanger, KY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		86,000
Gross Sales Price, Excluding Closing Costs		$ 2,600
Gain (Loss) on Sale of Real Estate		135
Loss on impairment of real estate		$ 2,184
Chesapeake, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		2
Rentable square feet (in square feet) | ft²		214,000
Gross Sales Price, Excluding Closing Costs		$ 24,000
Gain (Loss) on Sale of Real Estate		62
Loss on impairment of real estate		$ 649
Everett, WA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		2
Rentable square feet (in square feet) | ft²		112,000
Gross Sales Price, Excluding Closing Costs		$ 31,500
Gain (Loss) on Sale of Real Estate		$ 11,959
Salem, OR | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		233,000
Gross Sales Price, Excluding Closing Costs		$ 34,250
Gain (Loss) on Sale of Real Estate		$ 5,369
Kapolei, HI | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		109,000
Gross Sales Price, Excluding Closing Costs		$ 4,000
Gain (Loss) on Sale of Real Estate		$ 2,504
Eaglewood, CO | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		1
Rentable square feet (in square feet) | ft²		140,000
Gross Sales Price, Excluding Closing Costs		$ 11,100
Gain (Loss) on Sale of Real Estate		$ 860
Kansas City, MO | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			0
Rentable square feet (in square feet) | ft²			10,000
Gross Sales Price, Excluding Closing Costs			$ 845
Gain (Loss) on Sale of Real Estate			(63)
Loss on impairment of real estate			$ 0
Richmond, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		3	1
Rentable square feet (in square feet) | ft²		89,000	311,000
Gross Sales Price, Excluding Closing Costs		$ 5,350	$ 130,000
Gain (Loss) on Sale of Real Estate			54,181
Loss on impairment of real estate			$ 0
Huntsville, AL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			1,371,000
Gross Sales Price, Excluding Closing Costs			$ 39,000
Gain (Loss) on Sale of Real Estate			0
Loss on impairment of real estate			$ 5,383
Fresno, CA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			532,000
Gross Sales Price, Excluding Closing Costs			$ 6,000
Gain (Loss) on Sale of Real Estate			0
Loss on impairment of real estate			$ 33,902
Liverpool, NY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			38,000
Gross Sales Price, Excluding Closing Costs			$ 650
Gain (Loss) on Sale of Real Estate			31
Loss on impairment of real estate			$ 0
Memphis, TN | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			205,000
Gross Sales Price, Excluding Closing Costs			$ 15,270
Gain (Loss) on Sale of Real Estate			287
Loss on impairment of real estate			$ 0
Stoneham, MA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			98,000
Gross Sales Price, Excluding Closing Costs			$ 6,650
Gain (Loss) on Sale of Real Estate			(282)
Loss on impairment of real estate			$ 5,911
Sterling, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			0
Rentable square feet (in square feet) | ft²			0
Gross Sales Price, Excluding Closing Costs			$ 28,500
Gain (Loss) on Sale of Real Estate			24,200
Loss on impairment of real estate			$ 0
Number of land parcels | parcel_of_land			2
Stafford, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				2
Rentable square feet (in square feet) | ft²				65,000
Gross Sales Price, Excluding Closing Costs				$ 14,063
Gain (Loss) on Sale of Real Estate				4,771
Loss on impairment of real estate				$ 0
Windsor, CT | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				97,000
Gross Sales Price, Excluding Closing Costs				$ 7,000
Gain (Loss) on Sale of Real Estate				314
Loss on impairment of real estate				$ 0
Lincolnshire, IL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				223,000
Gross Sales Price, Excluding Closing Costs				$ 12,000
Gain (Loss) on Sale of Real Estate				1,179
Loss on impairment of real estate				$ 0
Trenton, NJ | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				267,000
Gross Sales Price, Excluding Closing Costs				$ 30,100
Gain (Loss) on Sale of Real Estate				(179)
Loss on impairment of real estate				$ 0
Fairfax, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				4
Rentable square feet (in square feet) | ft²				171,000
Gross Sales Price, Excluding Closing Costs				$ 25,100
Gain (Loss) on Sale of Real Estate				16
Loss on impairment of real estate				$ 2,954