Fair Value Measurements - Summary of Fair Value Measurements for Each Major Category of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	$ 162,179	$ 160,293
Other Liabilities, Fair Value Disclosure	162,179	160,293
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	440,123	338,951	$ 336,695	$ 463,400
Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	162,179	160,293
Other Liabilities, Fair Value Disclosure	162,179	160,293
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	0	0
Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	0	0
Other Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	440,123	338,951
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	0	0
Other Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	$ 0	$ 0