Indebtedness - Summary of Indebtedness at Estimated Fair Value (Details) - USD ($) $ in Thousands		Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Mortgage Loans Payable, Net		$ 86,609	$ 148,770
Senior Unsecured Notes, Net		1,084,772	1,096,262
Unsecured Term Loans		460,916	458,207
Unsecured Credit Facility		60,065	0
Total		1,692,362	1,703,239
Carrying Amount (A)
Debt Instrument [Line Items]
Mortgage Loans Payable, Net	[1]	83,902	144,214
Senior Unsecured Notes, Net	[1]	998,509	998,506
Unsecured Term Loans	[1]	460,000	460,000
Unsecured Credit Facility		60,000	0
Total	[1]	$ 1,602,411	$ 1,602,720

[1] The carrying amounts include unamortized premiums and discounts and exclude unamortized debt issuance costs.