Net Income Per Share - Summary of Dilutive Effect for Awards with Exercise Price Less Than Average Stock Price (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Weighted average common shares outstanding, basic	40,959	41,396	41,201
Dilutive potential common shares	0	0	0
Weighted average common shares outstanding, diluted	40,959	41,396	41,201
Shares excluded	5,975	5,468	5,915