Accumulated Other Comprehensive Income (Loss) - Summary of Components of AOCI (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Accumulated other comprehensive income (loss)	$ (4,115)	$ (2,200)
Other comprehensive income (loss)	1,900	(3,200)
Income tax benefit (expense)	(700)	1,200
Total other comprehensive income (loss)	1,138	(1,977)	$ (2,372)
Accumulated other comprehensive income (loss)	$ (2,977)	$ (4,115)	$ (2,200)