Stock Plans and Other Incentives - Changes in RSUs (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Employee	Dec. 31, 2012 Employee	Dec. 31, 2011 Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price	$ 19.23	$ 13.03	$ 9.12
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	80,139	84,367	44,019
Number of employees withholding tax obligations	16	16	14
Employee withholding tax obligations approx amount	$ 1,280,000	$ 851,000	$ 352,000
Common stock delivered, net	124,936	133,518	133,809