Segments - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Revenues, net	$ 577,877,000	$ 484,426,000	$ 1,639,547,000	$ 1,316,593,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues, net			$ 0