Revenues from Contracts with Customers - Summary of Impact to Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	$ 293,148	$ 210,471
Accrued compensation	205,732	205,395
Current portion of accounts payable, accrued expenses and other liabilities (see note 27)	165,746	$ 124,961
ASC 606 [Member] | Under Previous U.S. GAAP [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	214,695
Accrued compensation	168,338
Current portion of accounts payable, accrued expenses and other liabilities (see note 27)	148,466
ASC 606 [Member] | Effect of Change Higher/(Lower) [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	78,453
Accrued compensation	37,394
Current portion of accounts payable, accrued expenses and other liabilities (see note 27)	$ 17,280