Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net income	$ 76,870	$ 69,829	$ 69,118
Less: dividends and undistributed earnings allocated to participating securities	(223)	(152)	(139)
Net income available to common shareholders	$ 76,647	$ 69,677	$ 68,979
Weighted average common shares outstanding - basic	17,310,000	17,282,000	17,331,000
Basic earnings per common share (in dollars per share)	$ 4.43	$ 4.03	$ 3.98
Less dividends and undistributed earnings allocated to participating securities	$ (222)	$ (151)	$ (139)
Net income available to common shareholders	$ 76,648	$ 69,678	$ 68,979
Dilutive effect of common stock equivalents (in shares)	145,000	120,000	83,000
Weighted average common shares outstanding - diluted	17,455,000	17,402,000	17,414,000
Diluted earnings per common share (in dollars per share)	$ 4.39	$ 4.00	$ 3.96
Antidilutive common stock equivalents	100,150	223,506	100,643