(Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic (Loss) Earnings Per Share
Undistributed net (loss) income from operations	$ (15,803)	$ 16,323		$ 59,635
Basic net (loss) income attributable to common shares	$ (15,803)	$ 16,323	$ (59,470)	$ 59,635
Basic weighted average shares outstanding (in shares)	20,339,895	20,164,876	20,299,461	20,115,868
Basic undistributed net income (loss) per share attributable to common shares (USD per share)	$ (0.78)	$ 0.81	$ (2.93)	$ 2.96
Diluted (Loss) Earnings Per Share
Undistributed net (loss) income from operations	$ (15,803)	$ 16,323	$ (59,470)	$ 59,635
Diluted net (loss) income attributable to common shares	$ (15,803)	$ 16,323	$ (59,470)	$ 59,635
Basic weighted average shares outstanding (in shares)	20,339,895	20,164,876	20,299,461	20,115,868
Effect of dilutive options and restricted share units (in shares)	0	51,000	0	134,000
Diluted weighted average shares outstanding (in shares)	20,339,895	20,216,314	20,299,461	20,249,682
Diluted undistributed net income (loss) per share attributable to common shares (USD per share)	$ (0.78)	$ 0.81	$ (2.93)	$ 2.95