Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Outstanding stock options (in shares)	0	0	0	0
Distributed earnings allocated to common stock	$ 6,895	$ 6,491	$ 20,791	$ 18,420
Undistributed earnings allocated to common stock	17,402	13,272	48,827	42,141
Net earnings allocated to common stock	24,297	19,763	69,618	60,561
Net earnings allocated to participating securities	141	125	401	407
Net income available to common shareholders	$ 24,438	$ 19,888	$ 70,019	$ 60,968
Weighted average shares outstanding for basic earnings per common share	25,520,035	25,965,694	25,630,771	25,958,125
Dilutive effect of stock compensation (in shares)	0	0	0	0
Weighted average shares outstanding for diluted earnings per common share	25,520,035	25,965,694	25,630,771	25,958,125
Basic earnings per common share (in dollars per share)	$ 0.95	$ 0.76	$ 2.72	$ 2.33
Diluted earnings per common share (in dollars per share)	$ 0.95	$ 0.76	$ 2.72	$ 2.33