Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended		9 Months Ended	12 Months Ended			1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 23, 2014	Nov. 21, 2013	Sep. 30, 2014	Dec. 31, 2013	Nov. 21, 2013	Aug. 23, 2011	May 31, 2012 Stock Option	Sep. 30, 2013 Awards vested [Member]	Sep. 30, 2014 Awards vested [Member]	Sep. 30, 2013 Awards vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares options granted							190,000
Stock-based compensation expense								$ 500,000	$ 300,000	$ 500,000
Warrants issued to purchase common stock					1,000,000.0	1,000,000.0
Warrant exercise price						$ 9.62
Warrant Expiry Date	Aug. 23, 2014
Warrant's extended expiry period	August 23, 2017
Warrant exercise price		9,600,000
Repurchase of available common stock, authorized amount			85,000,000.0
Shares repurchased under stock repurchase program			1,700,000
Average Price Per Share			$ 17.68
Stock repurchase program remaining authorized repurchase amount			45,200,000
Stock repurchased value exclusive of purchase and administrative costs			$ 29,900,000	$ 10,000,000