Summary of Significant Accounting Policies - Net Income per Common Share (Details) - shares shares in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Anti-dilutive common stock equivalents related to options and restricted stock awards excluded from fully diluted calculation (in shares)	808	671	781
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average common shares outstanding—basic (in shares)	17,072	16,419	15,834
Dilutive common shares issuable in connection with stock plans (in shares)	0	0	0
Weighted average common shares outstanding—diluted (in shares)	17,072	16,419	15,834

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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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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met.

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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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