Income Taxes - Reconciliation of Federal Statutory Rate to Effective Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal income tax expense computed at statutory rate	$ 3,287	$ 46,760	$ 40,233
State income tax expense (benefit) — net of federal income tax	(4,491)	8,522	6,466
Valuation allowance — net	2,116	0	0
Intercompany interest	1,125	(5,213)	(8,367)
Permanent differences and other — net	1,655	1,940	(1,417)
Stock-based compensation	(12,901)	(10,990)	(9,446)
Unbenefited foreign loss	233	0	0
Change in income tax rate	(360)	0	(548)
Global Intangible Low-Taxed Income	(1,418)	1,277	2,893
Change to uncertain tax positions — net	(510)	(1,931)	1,657
Foreign rate differential	(76)	1,914	2,135
Income tax expense (benefit)	$ (11,340)	$ 42,279	$ 33,606