Supplemental Disclosures of Cash Flow Information - Summary of Amount Paid (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 82,494	$ 81,338	$ 74,792
Income taxes paid	$ 74,379	$ 79,790	$ 110,650