Summary of Significant Accounting Policies (Reconciliation of Net Income to Taxable Income Before Dividends Paid Deduction) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
REIT dividend distribution requirement percentage	90.00%
Net income (loss)	$ 861,618	$ 302,760	$ 432,644
Book/tax differences	(467,205)	63,838	(120,421)
Taxable income before adjustments	394,413	366,598	312,223
Less: capital gains	(33,652)	(62,165)	(62,513)
Adjusted taxable income subject to 90% distribution requirement	$ 360,761	$ 304,433	$ 249,710