Stock Plans - Schedule of Stock Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted stock	$ 3,035	$ 4,026	$ 4,129
Stock options	2,454	2,355	2,825
Performance stock	2,110	2,672	3,383
Total compensation expense before income taxes	7,599	9,053	10,337
Income tax benefit	2,896	3,293	3,810
Total compensation expense, net of income tax benefit	$ 4,703	$ 5,760	$ 6,527