Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 207,663	$ 210,910
Other comprehensive income (loss):
Net gain (loss) on cash flow hedges	(4,376)	5,414
Reclassification of net loss on cash flow hedges to income	627	740
Net actuarial loss	0	(5,944)
Amortization of prior service credit	(45)	(45)
Amortization of actuarial loss	1,348	5,114
Total other comprehensive income (loss)	(2,446)	5,279
Comprehensive income	$ 205,217	$ 216,189