Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 13,794	$ 14,725	$ 24,011	$ 26,276
Basic weighted average shares (in shares)	52,615,366	53,036,009	52,624,782	53,028,224
Effect of dilutive stock options and restricted stock (in shares)	535,768	538,693	551,643	535,452
Diluted weighted average shares (in shares)	53,151,134	53,574,702	53,176,425	53,563,676
Basic (usd per share)	$ 0.26	$ 0.28	$ 0.46	$ 0.47
Diluted (usd per share)	$ 0.26	$ 0.27	$ 0.45	$ 0.47
Anti-dilutive shares (in shares)	760,438	504,954	772,202	498,043

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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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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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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