Earnings Per Share (Details 2) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Distributed earnings allocated to common stock	$ 28,859	$ 28,188	$ 24,894
Undistributed earnings allocated to common stock	52,044	63,254	56,975
Net earnings allocated to common stock	80,903	91,442	81,869
Net earnings allocated to participating securities	534	518	545
Net income available to common shareholders	$ 81,437	$ 91,960	$ 82,414
Weighted average shares outstanding for basic earnings per common share	25,527,154	25,600,138	25,937,599
Dilutive effect of stock compensation (in shares)	0	0	0
Weighted average shares outstanding for diluted earnings per common share	25,527,154	25,600,138	25,937,599
Basic earnings per common share (in dollars per share)	$ 3.17	$ 3.57	$ 3.16
Diluted earnings per common share (in dollars per share)	$ 3.17	$ 3.57	$ 3.16