Income Taxes - Components of Provision for Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current provision:
Federal									$ 150,800	$ 102,516	$ 248,191
State									24,378	32,638	13,092
Total current provision									175,178	135,154	261,283
Deferred benefit:
Federal									(8,240)	(57,076)	(58,124)
State									(1,474)	(6,225)	(628)
Total deferred benefit									(9,714)	(63,301)	(58,752)
Provision for income tax expense	$ 34,666	$ 40,701	$ 33,801	$ 56,296	$ 44,449	$ (53,667)	$ 40,074	$ 40,997	$ 165,464	$ 71,853	$ 202,531