Earnings Per Common Share - Reconciliation of the Basic and Diluted EPS Denominators (Details) - shares shares in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reconciliation of the basic and diluted EPS denominators
Basic weighted-average common shares	32,561	31,063	32,383	30,922
Dilutive effect of restricted common stock	340	525	442	620
Dilutive effect of 2010 Convertible Notes		706		1,171
Dilutive effect of Stock Warrants		345		328
Diluted weighted-average common shares	32,901	32,639	32,825	33,041

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 23
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1757-109256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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.

+ References

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-Publisher FASB
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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.

+ References

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-Publisher FASB
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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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