Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Oct. 22, 2014	Nov. 01, 2007
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, additional authorized amount					$ 30,000,000
Repurchased shares	0	10,875	0	616,294
Repurchased shares, value		$ 109,000		$ 7,000,000
Stock repurchase program, average cost		$ 10.03		$ 11.34
Stock repurchase program, remaining available repurchase amount	$ 34,400,000		$ 34,400,000
Maximum
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, additional authorized amount						$ 50,000,000