Summary of Revenues Disaggregated Based on Timing of Revenue Recognition (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenues		$ 754,235	$ 710,748	$ 2,423,259	$ 2,241,553
U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	[1]	582,275		1,887,692
International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues		171,960		535,567
Goods and Services Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total revenues		717,140		2,306,928
Goods and Services Transferred at a Point in Time | U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	[1]	561,849		1,824,138
Goods and Services Transferred at a Point in Time | International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues		155,291		482,790
Goods and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenues		37,095		116,331
Goods and Services Transferred Over Time | U.S. Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues	[1]	20,426		63,554
Goods and Services Transferred Over Time | International Operating Segment
Disaggregation of Revenue [Line Items]
Total revenues		$ 16,669		$ 52,777

[1] U.S. segment revenues include eliminations of intercompany transactions with the international operating segment. See Note 15 for additional information on intercompany eliminations.