Significant Accounting Policies - Schedule of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accounting Policies [Abstract]
Weighted average common shares outstanding—basic (in shares)	37,528	37,371	37,527	37,562
Dilutive effect of common stock options and awards (in shares)	0	183	0	137
Weighted average common shares outstanding—diluted (in shares)	37,528	37,554	37,527	37,699