Real Estate Properties - Real Estate Properties Narrative (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($) property	Dec. 31, 2022 USD ($) ft² joint_venture property lease	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
Area of properties (in square feet) | ft²			926,000	163,000
Real estate aggregate undepreciated carrying value		$ 3,936,074	$ 3,911,086
Number of joint ventures | joint_venture		2
Number of leases entered | lease		75
Rentable square feet (in sqft) | ft²		2,562,000
Weighted average lease term		9 years 3 months 18 days
Expenditures committed on leases		$ 173,419
Operating leases committed expenditures on leases executed in period committed but unspent tenant related obligations		156,693
Loss on impairment of real estate		$ 21,820	$ 62,420	$ 2,954
Unconsolidated Joint Ventures
Real Estate Properties [Line Items]
Number of properties (in properties) | property		3
Area of properties (in square feet) | ft²		444,000
Number of joint ventures | joint_venture		2
Unconsolidated Joint Ventures | Mortgage Note Payable
Real Estate Properties [Line Items]
Interest rate (as a percent)		3.93%
Joint Venture Property 1
Real Estate Properties [Line Items]
Percentage of ownership interest		51.00%
Joint Venture Property 2
Real Estate Properties [Line Items]
Percentage of ownership interest		50.00%
Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		18	6	10
Area of properties (in square feet) | ft²		2,326,000	2,565,000	906,000
Gross Sales Price, Excluding Closing Costs		$ 211,020	$ 226,915	$ 110,463
Rentable Square Feet | ft²			2,565,000
Loss on impairment of real estate		$ 21,820	$ 45,196	$ 2,954
Number of real estate properties sold (in properties) | property			6	10
Disposal Group, Disposed of by Sale | Mortgage notes payable, 5.9% interest rate, due in 2021 | Mortgage Note Payable
Real Estate Properties [Line Items]
Extinguishment of debt, amount				$ 13,095
Interest rate (as a percent)				5.90%
Disposal Group, Disposed of by Sale | Sterling, VA
Real Estate Properties [Line Items]
Number of properties (in properties) | property			0
Area of properties (in square feet) | ft²			0
Gross Sales Price, Excluding Closing Costs			$ 28,500
Number of land parcels | parcel_of_land			2
Loss on impairment of real estate			$ 0
Disposal Group, Disposed of by Sale | Brookhaven, GA
Real Estate Properties [Line Items]
Number of properties (in properties) | property	3
Gross Sales Price, Excluding Closing Costs	$ 10,658
Loss on impairment of real estate			$ 425
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
Continuing Operations
Real Estate Properties [Line Items]
Area of properties (in square feet) | ft²		20,969,000
Real estate aggregate undepreciated carrying value		$ 3,938,658
Continuing Operations | Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Carrying value		$ 2,584