Significant Accounting Policies - Schedule of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Weighted average common shares outstanding—basic (in shares)	37,371	38,347	37,562	38,601
Dilutive effect of common stock options and awards (in shares)	183	201	137	188
Weighted average common shares outstanding—diluted (in shares)	37,554	38,548	37,699	38,789