Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued bonuses	$ 15,119	$ 15,866
Accrued payroll and severance	18,500	10,704
Accrued taxes	63,698	104,623
Accrued commissions/rebates	47,198	43,467
Other	93,957	64,152
Total	$ 238,472	$ 238,812