Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share
Net income for basic and diluted income per share	$ 4,377	$ 5,302
Shares of common stock and common stock equivalents:
Average common shares used in basic computation	32,890	32,949
Effect of dilutive securities (in shares)	1,103	1,181
Average common shares used in diluted computation	33,993	34,130
Income per share:
Basic (in dollars per share)	$ 0.13	$ 0.16
Diluted (in dollars per share)	$ 0.13	$ 0.16
Anti-dilutive equity awards not included in the detailed earnings per share computation
Equity awards not included in the diluted earnings per share computation	300,000	200,000

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 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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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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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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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.

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