Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended		12 Months Ended			18 Months Ended	20 Months Ended
	Apr. 30, 2013	Oct. 25, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 25, 2013	Dec. 31, 2014	Apr. 30, 2013	Oct. 25, 2011
Stockholders Equity Note [Line Items]
Stock repurchase program, authorized amount	$ 200,000	$ 250,000						$ 200,000	$ 250,000
Stock repurchase program, expiration date	Apr. 30, 2015	Apr. 25, 2013
Shares repurchased under repurchase program			7,125,988	0	8,481,453	13,986,349	27,717,428
Shares repurchased average price per share			$ 7.29		$ 7.72	$ 7.67	$ 5.73
Shares repurchased under repurchase program, value			52,070	107,167	65,611
Stock repurchase program, remaining authorized repurchase amount			41,317				41,317
Share Repurchase Program
Stockholders Equity Note [Line Items]
Shares repurchased under repurchase program, value			$ 51,927				$ 158,683
Equity Incentive Plan 2008
Stockholders Equity Note [Line Items]
Shares available for future grants			15,685,000				15,685,000
Share-based Compensation Arrangement by Share-based Payment Award, Description			The total number of shares of the Company’s Common Stock that may be granted under the 2008 Plan, as amended, is the sum of (i) 15,685,000 shares, and (ii) the number of shares subject to outstanding awards under the 1999 Plan that on or after April 16, 2008 either (a) cease for any reason to be subject to such awards (other than by reason of exercise or settlement of the awards to the extent they are exercised for or settled in vested and nonforfeitable shares of Common Stock) or (b) are surrendered by participants under the 1999 Plan or are retained by the Company to pay all or a portion of the exercise price and/or withholding taxes relating to such awards.
Equity Incentive Plan 2008 | Maximum Base Amount
Stockholders Equity Note [Line Items]
Shares available for future grants			8,223,673				8,223,673