Corporate Indebtedness - Senior Unsecured Notes (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Debt disclosures by scheduled maturity date
Accreted Balance	$ 1,242,994	$ 1,242,002
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	600,000
Accreted Balance	599,996	900,915
Deferred financing costs, net	(334)	(1,607)
Accreted Balance, net of deferred financing costs	599,662	899,308
Senior unsecured notes | 3.25 Percent Senior Unsecured Notes Due October 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	500,000
Accreted Balance	$ 499,996	499,913
Coupon Rate (as a percent)	3.25%
Initial Term (in Years)	5 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
Accreted Balance	$ 100,000	100,000
Coupon Rate (as a percent)	4.27%
Initial Term (in Years)	10 years
Senior unsecured notes | 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 0
Accreted Balance	$ 0	$ 301,002
Coupon Rate (as a percent)	0.00%
Initial Term (in Years)	10 years