Significant Accounting Policies - Schedule of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accounting Policies [Abstract]
Weighted average common shares outstanding—basic (in shares)	37,615	37,528	37,672	37,526
Dilutive effect of common stock options and awards (in shares)	0	190	0	180
Weighted average common shares outstanding—diluted (in shares)	37,615	37,718	37,672	37,706