Net Income Per Share - Summary of Dilutive Effect for Awards with Exercise Price Less than Average Stock Price (Detail) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Weighted average common shares outstanding, basic	41,034	41,088	41,589	41,048
Dilutive potential common shares	0	0	1,714	1,830
Weighted average common shares outstanding, diluted	41,034	41,088	43,303	42,878
Shares excluded	5,302	5,893	940	946