Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
(Benefit) provision for income taxes	$ (23,284)	$ 12,064
(Loss) income before income taxes	$ (42,871)	$ 48,497
Effective income tax rate	54.30%	24.90%
Tax Cuts and Jobs Act of 2017, incomplete accounting, provisional income tax benefit			$ 123,200
Tax Cuts and Jobs Act of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense			63,600
Unrecognized tax benefits	$ 63,200		$ 60,300
Decrease in unrecognized tax benefits is reasonably possible	$ 8,000