Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Computation of basic and diluted net income per common share
Net income	$ 4,950	$ 7,617
Weighted average common shares outstanding during the period (for basic calculation)	38,853	39,498
Dilutive effect of other potential common shares	27	124
Weighted average common shares and potential common shares (for diluted calculation)	38,880	39,622
Net income per common share - Basic	$ 0.13	$ 0.19
Net income per common share - Diluted	$ 0.13	$ 0.19
Stock awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive stock awards	400	100

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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