Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($)	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Preferred Stock [Member]	Common Stock Including Additional Paid in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances at Dec. 31, 2020			$ 0	$ 302,029,000	$ 134,039,000	$ 5,486,000	$ 441,554,000
Employee stock purchase plan				35,000			35,000
Dividend reinvestment plan				648,000			648,000
Stock-based compensation expense				1,725,000			1,725,000
Cash dividends					(13,880,000)		(13,880,000)
Net income					47,382,000		47,382,000
Change in net unrealized holding gain/(loss) on securities available for sale, net of tax effect						(5,782,000)	(5,782,000)
Stock grants to directors for retainer fees				344,000			344,000
Stock option exercises				50,000			50,000
Share repurchase program				(19,798,000)			(19,798,000)
Balances at Sep. 30, 2021			0	285,033,000	167,541,000	(296,000)	452,278,000
Balances at Jun. 30, 2021			0	293,232,000	157,150,000	1,506,000	451,888,000
Employee stock purchase plan				13,000			13,000
Dividend reinvestment plan				237,000			237,000
Stock-based compensation expense				448,000			448,000
Cash dividends					(4,660,000)		(4,660,000)
Net income					15,051,000		15,051,000
Change in net unrealized holding gain/(loss) on securities available for sale, net of tax effect						(1,802,000)	(1,802,000)
Stock option exercises				50,000			50,000
Share repurchase program				(8,947,000)			(8,947,000)
Balances at Sep. 30, 2021			0	285,033,000	167,541,000	(296,000)	452,278,000
Balances (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2021	$ 316,000	$ 316,000
Balances at Dec. 31, 2021			0	285,752,000	174,536,000	(3,729,000)	456,559,000
Employee stock purchase plan				33,000			33,000
Dividend reinvestment plan				653,000			653,000
Stock-based compensation expense				2,398,000			2,398,000
Cash dividends					(14,607,000)		(14,607,000)
Net income					39,260,000		39,260,000
Change in net unrealized holding gain/(loss) on securities available for sale, net of tax effect						(68,734,000)	(68,734,000)
Stock grants to directors for retainer fees				347,000			347,000
Stock option exercises				36,000			36,000
Balances at Sep. 30, 2022			0	289,219,000	199,505,000	(72,463,000)	416,261,000
Balances at Jun. 30, 2022			0	288,199,000	188,452,000	(47,668,000)	428,983,000
Employee stock purchase plan				12,000			12,000
Dividend reinvestment plan				218,000			218,000
Stock-based compensation expense				790,000			790,000
Cash dividends					(4,977,000)		(4,977,000)
Net income					16,030,000		16,030,000
Change in net unrealized holding gain/(loss) on securities available for sale, net of tax effect						(24,795,000)	(24,795,000)
Balances at Sep. 30, 2022			$ 0	$ 289,219,000	$ 199,505,000	$ (72,463,000)	$ 416,261,000