Net Income (Loss) Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Net Income (Loss) Per Common Share
Number of outstanding options not included in computation of Diluted EPS (in shares)	1,560,000	2,945,000
Numerator
Net Income (loss)	$ 9,620	$ (22,887)
Denominator
Weighted average number of common shares outstanding	51,457,000	51,467,000
Effect of outstanding share-based awards	935,000
Weighted average number of shares for diluted net income per common share	52,392,000	51,467,000
Basic earnings (loss) per share (in dollars per share)	$ 0.19us-gaap_EarningsPerShareBasic	$ (0.44)us-gaap_EarningsPerShareBasic
Diluted earnings (loss) per share (in dollars per share)	$ 0.18us-gaap_EarningsPerShareDiluted	$ (0.44)us-gaap_EarningsPerShareDiluted

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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