Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Basic Net Earnings Per Common Share [Abstract]
Earnings from continuing operations	$ 20,555	$ 16,827	$ 33,659	$ 25,424
Loss from discontinued operations	(1,123)	(882)	(2,011)	(1,490)
Net earnings available to common stockholders	$ 19,432	$ 15,945	$ 31,648	$ 23,934
Weighted average common shares outstanding (in shares)	22,328,292	22,471,428	22,374,785	22,484,894
Earnings from continuing operations per common share (in dollars per share)	$ 0.92	$ 0.75	$ 1.50	$ 1.13
Loss from discontinued operations per common share (in dollars per share)	(0.05)	(0.04)	(0.09)	(0.07)
Net earnings per common share - Basic (in dollars per share)	$ 0.87	$ 0.71	$ 1.41	$ 1.06
Diluted Net Earnings Per Common Share [Abstract]
Earnings from continuing operations	$ 20,555	$ 16,827	$ 33,659	$ 25,424
Loss from discontinued operations	(1,123)	(882)	(2,011)	(1,490)
Net earnings available to common stockholders	$ 19,432	$ 15,945	$ 31,648	$ 23,934
Weighted average common shares outstanding (in shares)	22,328,292	22,471,428	22,374,785	22,484,894
Plus incremental shares from assumed conversions [Abstract]
Dilutive effect of restricted stock and performance-based stock (in shares)	468,000	487,000	482,000	477,000
Weighted average common shares outstanding - Diluted (in shares)	22,795,677	22,958,469	22,857,435	22,962,049
Earnings from continuing operations per common share (in dollars per share)	$ 0.90	$ 0.73	$ 1.47	$ 1.11
Loss from discontinued operations per common share (in dollars per share)	(0.05)	(0.04)	(0.09)	(0.07)
Net earnings per common share - Diluted (in dollars per share)	$ 0.85	$ 0.69	$ 1.38	$ 1.04
Restricted and Performance-Based Shares [Member]
Earnings Per Share[Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	248,000	251,000	242,000	265,000