Other Current and Non-Current Liabilities - Schedule of Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Other Liabilities Current [Abstract]
Accrued accounts payable	$ 22,879	$ 38,046
Accrued compensation liability	26,050	33,815
Accrued restructuring liability	3,617	3,674
Accrued payable from acquisitions	10,000	12,800
Accrued lease incentive obligation	24,895	20,059
Value-added taxes payable	3,538	3,453
Other current liabilities	8,846	11,242
Total other current liabilities	$ 99,825	$ 123,089