Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of basic and diluted earnings per share (EPS)
Net income (loss)	$ (5,988)	$ (3,803)	$ (13,527)	$ (9,984)	$ (6,734)	$ 32,627	$ (23,318)	$ 15,909
Less: Preferred stock dividend	125			125			371	332
Less: Earnings attributable to participating securities							0	1,957
(Loss) income attributable to common stockholders	$ (6,113)			$ (10,109)			(23,689)	13,620
Effect of dilutive securities:
Add back: Allocation of earnings to participating securities							0	1,957
Less: Re-allocation of earnings to participating securities considering potentially dilutive securities							0	(1,951)
Numerator for diluted EPS							$ (23,689)	$ 13,626
Basic loss per Common Share
Weighted-average common shares outstanding (in shares)	6,291			6,250			6,277	6,230
Basic (loss) income per common share (in dollars per share)	$ (0.97)			$ (1.62)			$ (3.77)	$ 2.19
Diluted Loss per Common Share
Weighted-average shares used to compute earnings/(loss) per share attributable to common shares (in shares)	6,291			6,250			6,277	6,251
Diluted (loss) income per common share (in dollars per share)	$ (0.97)			$ (1.62)			$ (3.77)	$ 2.18
Unvested shares (in shares)							0	21
Computation of Shares Used in Diluted Loss Per Common Share
Weighted-average common shares outstanding (in shares)	6,291			6,250			6,277	6,230
Weighted-average shares used to compute earnings/(loss) per share attributable to common shares (in shares)	6,291			6,250			6,277	6,251
Stock-based compensation arrangement by stock-based payment award
Dividend rate (as percent)							5.00%
Stock Options
Stock-based compensation arrangement by stock-based payment award
Weighted-average anti-dilutive shares have been excluded from the EPS calculations (in shares)	100			200			100	300
Unvested Shares
Stock-based compensation arrangement by stock-based payment award
Weighted-average anti-dilutive shares have been excluded from the EPS calculations (in shares)	200			100			200	100
Preferred Stock
Stock-based compensation arrangement by stock-based payment award
Weighted-average anti-dilutive shares have been excluded from the EPS calculations (in shares)							1,000	0