Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Expense of defined contribution retirement plans	$ 1,255	$ 1,651	$ 1,456
Unfunded liability for supplemental plan	$ 802	$ 715