Net Income (Loss) per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator for earnings per share:
Net income (loss) that is available to common shareholders	$ (43,767)	$ 3,988	$ (48,309)	$ 1,027
Denominator for basic earnings per share:
Weighted average shares outstanding	22,400,246	22,170,338	22,331,786	22,130,503
Denominator for diluted earnings per share:
Effect of stock options and restricted stock units	0	185,550	0	36,584
Adjusted weighted average shares and assumed conversions	22,400,246	22,355,888	22,331,786	22,167,087
Basic income (loss) per share	$ (1.95)	$ 0.18	$ (2.16)	$ 0.05
Diluted income (loss) per share	$ (1.95)	$ 0.18	$ (2.16)	$ 0.05
Anti-dilutive shares excluded from computation of diluted income (loss) per share	1,939,290	752,375	1,700,192	982,386

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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