Earnings per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Numerator for basic and diluted EPS — net income (loss)	$ 6,368	$ (746)
Denominator for basic EPS — weighted average number of shares (shares)	29,754,957	31,904,270
Add — dilutive effect of:
Weighted average number of incremental shares issuable from restricted stock units (shares)	444,000	0
Denominator for diluted EPS — weighted average number of shares and dilutive potential shares (shares)	30,198,797	31,904,270
Earnings per share:
Basic (usd per share)	$ 0.21	$ (0.02)
Diluted (usd per share)	$ 0.21	$ (0.02)
Antidilutive securities excluded from EPS (shares)	1,255,997	2,722,509
Cogent Partners, LP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incremental common shares excluded from dilutive effect of contingently issuable shares (shares)	334,048

Incremental Common Shares Excluded From Dilutive Effect of Contingently Issuable Shares

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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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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.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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