Corporate Indebtedness - Senior Unsecured Notes (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2021	Dec. 31, 2020
Debt disclosures by scheduled maturity date
Accreted Balance		$ 899,308,000	$ 1,248,219,000
Deferred financing costs, net		(5,537,000)	(21,388,000)
Senior Unsecured Bonds | 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Coupon Rate (as a percent)	4.50%
Face amount of loan	$ 100,000,000
Redemption price, percentage	105.334%
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		900,000,000
Accreted Balance		900,915,000	1,251,889,000
Deferred financing costs, net		(1,607,000)	(3,670,000)
Senior notes, net of deferred finance costs		899,308,000	1,248,219,000
Senior unsecured notes | 3.25% Senior unsecured notes maturing October 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		500,000,000
Accreted Balance		$ 499,913,000	499,803,000
Coupon Rate (as a percent)		3.25%
Initial Term (in Years)		5 years
Senior unsecured notes | 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 300,000,000
Accreted Balance		$ 301,002,000	302,086,000
Coupon Rate (as a percent)		4.50%
Initial Term (in Years)		10 years
Senior unsecured notes | 4.27% Senior unsecured notes maturing on December 17, 2025
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 100,000,000
Accreted Balance		$ 100,000,000	100,000,000
Coupon Rate (as a percent)		4.27%
Initial Term (in Years)		10 years
Senior unsecured notes | Senior unsecured notes maturing August 2021
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 0
Accreted Balance		$ 0	$ 350,000,000
Coupon Rate (as a percent)		0.00%
Initial Term (in Years)		3 years