Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Non-cash investing and financing activities:
Purchase of property and equipment in accounts payable	$ 4,364	$ 1,784	$ 574
Additional cash payment information:
Interest paid	1,467	818	903
Income tax paid	$ 16,409	$ 9,393	$ 146