Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Disclosure Summary Of Accrued Expenses And Other Current Liabilities [Abstract]
Accrued payroll		$ 143,431	$ 158,006
Accrued payroll		20,529	35,122
Other employee related liabilities		43,255	60,889
Other		98,946	76,229
Total accrued expenses and other current liabilities	[1]	$ 306,161	$ 330,246

[1] We adopted Topic 842 using the modified retrospective method as of January 1, 2019 and elected the transition option that allows us not to restate the comparative periods in our condensed consolidated financial statements in the year of adoption. See Note 2 for further details.