Derivative and Other Fair Value Instruments - Summary of Fair Value Measurements for Each Major Category of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	$ 160,293	$ 151,889
Other Liabilities, Fair Value Disclosure	160,293	151,889
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	338,951	463,400	$ 379,106	$ 366,955
Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	160,293	151,889
Other Liabilities, Fair Value Disclosure	160,293	151,889
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	338,951	463,400
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