Income Taxes (Details) - Current and Long-Term Deferred Tax Assets and Liabilities - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Accrued liabilities	$ 80,557	$ 62,439
Loss and credit carryforwards	59,502	7,766
Assets relating to equity compensation	24,874	25,569
Other assets	30,236	6,652
Gross deferred tax assets	195,169	102,426
Property, equipment, and leasehold improvements	(962)	(11,796)
Intangible assets	(372,542)	(43,548)
Prepaid expenses	(35,126)	(32,971)
Other liabilities	(6,584)	(7,925)
Gross deferred tax liabilities	(415,214)	(96,240)
Valuation allowance	(3,192)	(1,431)
Net deferred tax (liabilities)	$ 223,237
Net deferred tax assets		$ 4,755