Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic Net Earnings Per Common Share [Abstract]
Earnings from continuing operations	$ 12,157	$ 19,273	$ 16,827	$ 8,597	$ (8,106)	$ 17,108	$ 18,261	$ 16,367	$ 56,854	$ 43,630	$ 62,412
Loss from discontinued operations, net of taxes	$ (8,837)	$ (3,524)	$ (882)	$ (608)	$ (541)	$ (3,983)	$ (497)	$ (633)	(13,851)	(5,654)	(1,982)
Net earnings available to common stockholders									$ 43,003	$ 37,976	$ 60,430
Weighted average common shares outstanding (in shares)									22,456,480	22,726,491	22,722,517
Earnings from continuing operations per common share (in dollars per share)	$ 0.54	$ 0.86	$ 0.75	$ 0.38	$ (0.36)	$ 0.75	$ 0.80	$ 0.72	$ 2.53	$ 1.92	$ 2.75
Loss from discontinued operations per common share (in dollars per share)									(0.62)	(0.25)	(0.09)
Net earnings per common share - Basic (in dollars per share)	$ 0.15	$ 0.70	$ 0.71	$ 0.36	$ (0.38)	$ 0.58	$ 0.78	$ 0.69	$ 1.91	$ 1.67	$ 2.66
Diluted Net Earnings Per Common Share [Abstract]
Earnings from continuing operations	$ 12,157	$ 19,273	$ 16,827	$ 8,597	$ (8,106)	$ 17,108	$ 18,261	$ 16,367	$ 56,854	$ 43,630	$ 62,412
Loss from discontinued operations, net of taxes	$ (8,837)	$ (3,524)	$ (882)	$ (608)	$ (541)	$ (3,983)	$ (497)	$ (633)	(13,851)	(5,654)	(1,982)
Net earnings available to common stockholders									$ 43,003	$ 37,976	$ 60,430
Weighted average common shares outstanding (in shares)									22,456,480	22,726,491	22,722,517
Plus incremental shares from assumed conversions [Abstract]
Dilutive effect of restricted stock and performance-based stock (in shares)									476,000	472,000	360,000
Weighted average common shares outstanding - Diluted (in shares)									22,931,723	23,198,392	23,082,578
Earnings from continuing operations per common share (in dollars per share)	$ 0.53	$ 0.84	$ 0.73	$ 0.37	$ (0.36)	$ 0.74	$ 0.78	$ 0.70	$ 2.48	$ 1.88	$ 2.70
Loss from discontinued operations per common share (in dollars per share)									(0.60)	(0.24)	(0.08)
Net earnings per common share - Diluted (in dollars per share)	$ 0.14	$ 0.69	$ 0.69	$ 0.35	$ (0.38)	$ 0.57	$ 0.76	$ 0.67	$ 1.88	$ 1.64	$ 2.62
Restricted and Performance Shares [Member]
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)									249,000	248,000	304,000