Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Oct. 22, 2014	Nov. 01, 2007
Equity [Abstract]
Stock repurchase program, additional authorized amount					$ 30,000,000	$ 50,000,000
Repurchased shares	0	534,849	0	1,151,143
Repurchased shares, value		$ 5,000,000		$ 12,000,000
Stock repurchase program, average cost		$ 9.36		$ 10.42
Stock repurchase program, remaining available repurchase amount	$ 34,400,000		$ 34,400,000