Indebtedness - Summary of Indebtedness at Estimated Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Mortgage Loans Payable, Net	$ 148,770	$ 179,287
Senior Unsecured Notes, Net	1,096,262	756,351
Unsecured Term Loans	458,207	460,902
Unsecured Credit Facility	0	158,141
Total	1,703,239	1,554,681
Carrying Amount (A)
Debt Instrument [Line Items]
Mortgage Loans Payable, Net	144,214	174,360
Senior Unsecured Notes, Net	998,506	698,500
Unsecured Term Loans	460,000	460,000
Unsecured Credit Facility	0	158,000
Total	$ 1,602,720	$ 1,490,860