Significant Accounting Policies - Schedule of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accounting Policies [Abstract]
Weighted average common shares outstanding—basic (in shares)	37,528	37,564	37,526	37,658
Dilutive effect of common stock options and awards (in shares)	190	149	180	121
Weighted average common shares outstanding—diluted (in shares)	37,718	37,713	37,706	37,779