Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Dividend rate (as percent)					5.00%
Reconciliation of basic and diluted earnings per share (EPS)
Net (loss) income	$ (3,803)	$ (13,527)	$ (6,734)	$ 32,629	$ (17,330)	$ 25,893
Less: Preferred stock dividend	124		124		246	207
Less: Earnings attributable to participating securities					0	3,059
(Loss) income attributable to common stockholders	$ (3,927)		$ (6,858)		(17,576)	22,627
Effect of dilutive securities:
Add back: Allocation of earnings to participating securities					0	3,059
Less: Re-allocation of earnings to participating securities considering potentially dilutive securities					0	(3,046)
Numerator for diluted EPS					$ (17,576)	$ 22,640
Basic earnings (loss) per common share
Weighted-average common shares outstanding (in shares)	6,272		6,226		6,270	6,220
Basic (loss) income per common share (in dollars per share)	$ (0.63)		$ (1.10)		$ (2.80)	$ 3.64
Diluted Loss per Common Share
Weighted-average shares used to compute earnings/(loss) per share attributable to common shares (in shares)	6,272		6,226		6,270	6,250
Diluted (loss) income per common share (in dollars per share)	$ (0.63)		$ (1.10)		$ (2.80)	$ 3.62
Unvested shares (in shares)					0	30
Computation of Shares Used in Diluted Loss Per Common Share
Weighted-average common shares outstanding (in shares)	6,272		6,226		6,270	6,220
Weighted-average shares used to compute earnings/(loss) per share attributable to common shares (in shares)	6,272		6,226		6,270	6,250
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		300		300	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		200		200	32
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