Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 153,383	$ 38,292	$ 30,118
Net earnings	$ 56,446	$ 15,877	$ 19,708
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	$ 5.49	$ 1.37	$ 1.09
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic and Diluted Share	5.46	1.36	1.06
Diluted earnings per share (in dollars per share)	$ 7.47	$ 1.92	$ 1.75
Basic:
Weighted average number of shares outstanding (in shares)	27,936,000	27,945,000	27,611,000
Diluted:
Weighted average number of shares outstanding (in shares)	27,936,000	27,945,000	27,611,000
Earnings Per Share, Basic (in dollars per share)	$ 7.51	$ 1.94	$ 1.80
Weighted average shares issuable on exercise of dilutive stock options (in shares)	156,000	208,000	160,000
Weighted average shares issuable on exercise of convertible notes (in shares)	0	37,000	466,000
Weighted average shares issuable on exercise of warrants related to 2017 Notes (in shares)	0	33,000	181,000
Weighted average number of shares outstanding, diluted (in shares)	28,092,000	28,223,000	28,418,000
Equity awards granted to employees
Diluted:
Antidilutive securities excluded from computation of earnings per share (in shares)	339,961	186,115	245,361
2013 Management Incentive Plan [Member] | Performance-based and Market-based Stock Awards [Member] | 2016 Grant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	130.00%