Accumulated Other Comprehensive Income (Summary of Amounts Reclassified Out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Reclassifications out of accumulated other comprehensive income (loss)
(Gains) losses on cash flow hedges	$ 34,210	$ 34,448
Income taxes on (gains) losses on cash flow hedges	(21,205)	(34,100)
Total reclassifications of (income) loss, net of tax for the period	68,159	125,082
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	2,973	1,150
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	3,801	1,407
Income taxes on (gains) losses on cash flow hedges	$ (828)	$ (257)