Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator
Net income (loss) - basic and diluted	$ (23,870)	$ (1,441)	$ (62,262)	$ 4,147
Denominator
Weighted average common shares outstanding - basic (in shares)	90,535	89,675	90,056	89,863
Dilutive effect of stock options and restricted stock awards (in shares)	0	0	0	1,676
Dilutive effect of Convertible Notes (in shares)	0	0	0	0
Weighted average common shares outstanding - diluted (in shares)	90,535	89,675	90,056	91,539
Net income (loss) per common share
Basic (in dollars per share)	$ (0.26)	$ (0.02)	$ (0.69)	$ 0.05
Diluted (in dollars per share)	$ (0.26)	$ (0.02)	$ (0.69)	$ 0.05
Stock options and restricted stock awards (in shares)	5,608	4,989	5,172	1,812