Accumulated Other Comprehensive Income (Summary of Amounts Reclassified Out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassifications out of accumulated other comprehensive income (loss)
(Gains) losses on cash flow hedges	$ 31,439	$ 32,397	$ 65,649	$ 66,845
Income taxes on (gains) losses on cash flow hedges	(1,550)	(6,844)	(22,755)	(40,944)
Total reclassifications of (income) loss, net of tax for the period	(3,617)	34,103	64,542	159,185
Amounts reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income (loss)
Total reclassifications of (income) loss, net of tax for the period	3,041	3,359	6,014	4,509
Accumulated Other Comprehensive Income (Loss) Components | Amounts reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income (loss)
(Gains) losses on cash flow hedges	3,888	4,103	7,689	5,510
Income taxes on (gains) losses on cash flow hedges	$ (847)	$ (744)	$ (1,675)	$ (1,001)