Schedule of Impact of Adoption on Condensed Consolidated Income Statement (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Net Revenue before provision for doubtful accounts		$ 2,825,472
Less: Provision for doubtful accounts		212,614
Net Revenues	$ 2,687,516	2,612,858
Other operating expenses	620,819	$ 607,360
Balances Without Adoption ASC 606 | ASU 2014-09
Disaggregation Of Revenue [Line Items]
Net Revenue before provision for doubtful accounts	2,931,527
Less: Provision for doubtful accounts	246,543
Net Revenues	2,684,984
Other operating expenses	618,287
Effect of Change | ASU 2014-09
Disaggregation Of Revenue [Line Items]
Net Revenues	2,532
Other operating expenses	$ 2,532