Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic Earnings Per Share:
Net income available to common shareholders	$ 11,737	$ 5,140
Less: Income allocated to participating securities	3	1
Net income allocated to common shareholders	$ 11,734	$ 5,139
Weighted average common shares outstanding Including participating securities	10,176	9,446
Less: Participating securities	11	5
Average common shares	10,165	9,441
Basic earnings per common share	$ 1.15	$ 0.54
Diluted Earnings Per Share:
Net income allocated to common shareholders	$ 11,734	$ 5,139
Weighted average common shares outstanding for basic earnings per common share	10,165	9,441
Add: Dilutive effects of stock options	54	56
Average shares and dilutive potential common shares	10,219	9,497
Diluted earnings per common share	$ 1.15	$ 0.54