Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator
Net income (loss) - basic and diluted	$ (12,148)	$ 1,282
Denominator
Weighted average common shares outstanding - basic (in shares)	89,645	90,111
Dilutive effect of stock options and restricted stock awards (in shares)	0	2,267
Dilutive effect of 2021 Convertible Notes (in shares)	0	0
Weighted average common shares outstanding - diluted (in shares)	89,645	92,378
Net income (loss) per common share
Basic (in dollars per share)	$ (0.14)	$ 0.01
Diluted (in dollars per share)	$ (0.14)	$ 0.01
Stock options and restricted stock excluded from calculation of diluted earnings per share because anti-dilutive for the period (in shares)	4,835	1,712