Comprehensive Income and Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (AOCI) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	$ 2,810	$ (4,295)	$ 2,979
Other comprehensive income (loss) before reclassification	(1,584)	6,558	(7,525)
Amounts reclassified from accumulated other comprehensive income	1,361	547	251
Net current period other comprehensive income (loss)	(223)	7,105	(7,274)
Ending balance	$ 2,587	$ 2,810	$ (4,295)