Summary of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earning per share reconciliation
Net income (loss)	$ 8,710	$ (331)	$ 22,482	$ 1,459
Weighted-average common shares outstanding, basic	37,955	37,881	37,950	37,834
Earnings (loss) per share, basic	$ 0.23	$ (0.01)	$ 0.59	$ 0.04
Net income (loss)	$ 8,710	$ (331)	$ 22,482	$ 1,459
Weighted-average common shares outstanding, basic	37,955	37,881	37,950	37,834
Effect of assumed exercise of stock options, warrants and RSUs	1,124		922	1,063
Weighted-average common shares outstanding, diluted	39,079	37,881	38,872	38,897
Earnings (loss) per share, diluted	$ 0.22	$ (0.01)	$ 0.58	$ 0.04
Outstanding options and RSUs excluded as impact would be antidilutive	33	1,865	146	55
Stock Options
Earning per share reconciliation
Weighted-average effect of dilutive securities	913		729	817
RSUs
Earning per share reconciliation
Weighted-average effect of dilutive securities	211		193	246