Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 692	$ 153,383	$ 38,292
Net (loss) earnings	$ (70,434)	$ 56,446	$ 15,877
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	$ 0.02	$ 5.49	$ 1.37
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic and Diluted Share	0.02	5.46	1.36
Diluted earnings per share (in dollars per share)	$ (2.52)	$ 7.47	$ 1.92
Basic:
Weighted average number of shares outstanding (in shares)	27,723,000	27,936,000	27,945,000
Diluted:
Weighted average number of shares outstanding (in shares)	27,723,000	27,936,000	27,945,000
Earnings Per Share, Basic (in dollars per share)	$ (2.52)	$ 7.51	$ 1.94
Weighted average shares issuable on exercise of dilutive stock options (in shares)	0	156,000	208,000
Weighted average shares issuable on exercise of convertible notes (in shares)	0	0	37,000
Weighted average shares issuable on exercise of warrants related to 2017 Notes (in shares)	0	0	33,000
Weighted average number of shares outstanding, diluted (in shares)	27,723,000	28,092,000	28,223,000
Equity awards granted to employees
Diluted:
Antidilutive securities excluded from computation of earnings per share (in shares)	597,904	339,961	186,115
Corporate stock
Diluted:
Weighted average shares issuable on exercise of convertible notes (in shares)	40,979