Other Current and Non-Current Liabilities - Schedule of Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Other Liabilities Current [Abstract]
Accrued accounts payable	$ 46,171	$ 22,669
Accrued compensation liability	34,352	41,554
Accrued restructuring liability		3,449
Contingent consideration payable	112,200	17,300
Accrued payable from acquisitions	25,000	35,000
Accrued lease incentive obligation		24,895
Value-added taxes payable	3,647	2,624
Other current liabilities	8,512	9,338
Total other current liabilities	$ 229,882	$ 156,829