Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Numerator
Net income	$ 1,282	$ 7,222
Denominator
Basic - weighted average common shares outstanding (in shares)	90,111	89,094
Dilutive effect of stock options and restricted stock awards (in shares)	2,267	2,637
Weighted average common shares outstanding - diluted (in shares)	92,378	91,731
Net income per common share
Income (loss) per common share - basic (in dollars per share)	$ 0.01	$ 0.08
Income (loss) per common share - diluted (in dollars per share)	$ 0.01	$ 0.08
Stock options and restricted stock excluded from calculation of diluted earnings per share because anti-dilutive for the period (in shares)	1,712	1,654
Convertible debt \| Convertible Notes due 2021
Denominator
Dilutive effect of Convertible Notes (in shares)	0	0
Senior notes \| Convertible Notes due 2021
Net income per common share
Debt instrument, convertible, conversion price (in dollars per share)	$ 9.33

Earnings (Loss) Per Share, Basic and Diluted [Abstract]

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The price per share of the conversion feature embedded in the debt instrument.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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