Indebtedness - Summary of Indebtedness at Estimated Fair Value (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Mortgage Loans Payable, Net		$ 161,311	$ 179,287
Senior Unsecured Notes, Net		1,092,155	756,351
Unsecured Term Loans		458,968	460,902
Unsecured Credit Facility		0	158,141
Total		1,712,434	1,554,681
Carrying Amount (A)
Debt Instrument [Line Items]
Mortgage Loans Payable, Net	[1]	155,706	174,360
Senior Unsecured Notes, Net	[1]	998,505	698,500
Unsecured Term Loans	[1]	460,000	460,000
Unsecured Credit Facility	[1]	0	158,000
Total	[1]	$ 1,614,211	$ 1,490,860

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