Stock Plans and Other Incentives - Changes in RSUs (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) Employee $ / shares shares	Dec. 31, 2013 USD ($) Employee $ / shares shares	Dec. 31, 2014 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price | $ / shares	$ 23.73	$ 19.23	$ 26.17
RSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock used to settle minimum employee withholding tax obligations	41,136	80,139
Number of employees withholding tax obligations | Employee	28	16
Employee withholding tax obligations approximate amount | $	$ 993,000	$ 1,280,000
Common stock delivered, net	64,834	124,936