Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Equity [Abstract]
Stock repurchase program, authorized amount	$ 50		$ 50
Repurchased shares	534,849	0	1,151,143	0
Repurchased shares, value	5.0		12.0
Stock repurchase program, average cost	$ 9.36		$ 10.42
Stock repurchase program, remaining available repurchase amount	$ 7.4		$ 7.4