Summary of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earning per share reconciliation
Net income	$ 3,104	$ 1,504	$ 9,039	$ 11,269
Weighted-average common shares outstanding	76,626	76,286	76,514	76,385
Earnings per share, basic	$ 0.04	$ 0.02	$ 0.12	$ 0.15
Net income	$ 3,104	$ 1,504	$ 9,039	$ 11,269
Weighted-average common shares outstanding, basic	76,626	76,286	76,514	76,385
Effect of assumed exercise of stock options and RSUs	2,324	1,994	2,257	2,178
Weighted-average common shares outstanding, diluted	78,950	78,280	78,771	78,563
Earnings per share, diluted	$ 0.04	$ 0.02	$ 0.11	$ 0.14
Outstanding options and RSUs excluded as impact would be anti-dilutive	223	166	141	112
Stock Options
Earning per share reconciliation
Weighted-average effect of dilutive securities	1,525	1,607	1,517	1,766
RSUs
Earning per share reconciliation
Weighted-average effect of dilutive securities	799	387	740	412