Income Taxes - Reconciliation of Statutory Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected tax at statutory rate	$ 97,110	$ 95,828	$ 186,274
Non-taxable REIT income	(82,717)	(83,022)	(170,811)
State and local tax expense - net of federal benefit	2,837	2,385	2,306
Change in valuation allowance	(207)	(1,052)	159
Tax credits/true-up	(3,663)	(6,016)	(5,956)
Remeasurement of deferred balances	0	0	(8,460)
Miscellaneous	(2,052)	1,121	113
Total provision	$ 11,308	$ 9,244	$ 3,625
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Expected tax at statutory rate	21.00%	21.00%	35.00%
Non-taxable REIT income	(17.90%)	(18.20%)	(32.10%)
State and local tax expense - net of federal benefit	0.60%	0.50%	0.40%
Change in valuation allowance	0.00%	(0.20%)	0.00%
Tax credits/true-up	(0.80%)	(1.30%)	(1.10%)
Remeasurement of deferred balances	0.00%	0.00%	(1.60%)
Miscellaneous	(0.40%)	0.20%	0.00%
Total provision	2.50%	2.00%	0.60%