Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 140,064	$ 330,191	$ 322,940
State	32,990	47,228	44,525
International	7,557	3,422	1,928
Total current income tax	180,611	380,841	369,393
Deferred:
Federal	52,034	(98,760)	88,412
State	21,096	37,347	(28,530)
International	4,659	4,431	2,486
Total deferred income tax	77,789	(56,982)	62,368
Continuing operations	$ 258,400	$ 323,859	$ 431,761