Stockholders' Equity - Common Stock Purchased Including Purchase of Common Stock for Tax Withholdings (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended												12 Months Ended			36 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	0	0	108,459	0	277,191	434,982	0	21,657	0	0	0	20,027	108,459	733,830	20,027	862,316
Average Price Paid Per Share	$ 0.00	$ 0.00	$ 12.92	$ 0.00	$ 11.26	$ 11.30	$ 0.00	$ 14.10	$ 0.00	$ 0.00	$ 0.00	$ 15.21	$ 12.92	$ 11.37	$ 15.21	$ 11.65
Publicly Announced Plans or Programs [Member]
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	0	0	0	0	277,191	434,982	0	0	0	0	0	0	0	712,173	0	712,173
Dollar Value of Shares That May Yet Be Purchased Under the Publicly Announced Plans or Programs	$ 16,964	$ 16,964	$ 16,964	$ 16,964	$ 16,964	$ 20,085	$ 16,135	$ 16,135	$ 16,135	$ 16,135	$ 16,135	$ 16,135