Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic and Diluted Earnings per Share [Line Items]
Net income from continuing operations	$ 20,364	$ 18,584
Weighted-average common shares outstanding (in shares)	24,915,772	25,443,101
Weighted-average common shares for EPS calculation (in shares)	25,458,090	25,854,181
Earnings (loss) per common share from continuing operations, basic (in dollars per share)	$ 0.82	$ 0.73
Earnings (loss) per common share from continuing operations, diluted (in dollars per share)	0.80	0.72
Earnings per common share from discontinued operations, basic (in dollars per share)	(0.08)	0.05
Earnings per common share from discontinued operations, diluted (in dollars per share)	(0.07)	0.05
Gain on sale of discontinued operations, net of taxes, basic (in dollars per share)	1.10	0.00
Gain on sale of discontinued operations, net of taxes, diluted (in dollars per share)	1.07	0.00
Earnings (loss) per common share, basic (in dollars per share)	1.84	0.78
Earnings (loss) per common share, diluted (in dollars per share)	$ 1.80	$ 0.77
Awards excluded from diluted earnings per share calculation (in shares)	0	0
Restricted Stock Unit Awards
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)	290,083	248,717
Stock Options
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)	252,235	162,363