Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Capital Surplus	Capital Surplus Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive (Loss)	Accumulated Other Comprehensive (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning Balance at Dec. 31, 2022	$ 577,852	$ 175	$ 578,027	$ 47,619	$ 47,619	$ 170,980	$ 170,980	$ 706,696	$ 175	$ 706,871	$ (215,955)	$ (215,955)	$ (131,488)	$ (131,488)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	86,913			0		0		86,913			0		0
Other comprehensive income (loss)	(35,105)			0		0		0			0		(35,105)
Cash dividends declared	(30,359)			0		0		(30,359)			0		0
Stock-based compensation expense	2,407			0		2,407		0			0		0
Restricted awards granted	0			0		(3,848)		0			3,848		0
Purchase of treasury shares	(53,827)			0		0		0			(53,827)		0
Acquisition of Citizens Commerce Bancshares, Inc.	62,078			0		7,574		0			54,504		0
Ending balance at Sep. 30, 2023	610,134			47,619		177,113		763,425			(211,430)		(166,593)
Beginning Balance at Jun. 30, 2023	636,192			47,619		176,746		744,248			(201,973)		(130,448)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,839			0		0		29,839			0		0
Other comprehensive income (loss)	(36,145)			0		0		0			0		(36,145)
Cash dividends declared	(10,662)			0		0		(10,662)			0		0
Stock-based compensation expense	681			0		681		0			0		0
Restricted awards granted	0			0		(314)		0			314		0
Purchase of treasury shares	(9,771)			0		0		0			(9,771)		0
Ending balance at Sep. 30, 2023	610,134			47,619		177,113		763,425			(211,430)		(166,593)
Beginning Balance at Dec. 31, 2023	677,066			47,619		177,424		780,299			(217,737)		(110,539)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	88,447			0		0		88,447			0		0
Other comprehensive income (loss)	23,675			0		0		0			0		23,675
Cash dividends declared	(32,968)			0		0		(32,968)			0		0
Stock-based compensation expense	2,683			0		2,683		0			0		0
Restricted awards granted	0			0		(4,312)		0			4,312		0
Exercise of stock options	292			0		(193)		0			485		0
Purchase of treasury shares	(17,896)			0		0		0			(17,896)		0
Ending balance at Sep. 30, 2024	$ 741,299			47,619		175,602		835,778			(230,836)		(86,864)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	5,009
Beginning Balance at Jun. 30, 2024	$ 686,740			47,619		174,834		817,549			(230,944)		(122,318)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,809			0		0		29,809			0		0
Other comprehensive income (loss)	35,454			0		0		0			0		35,454
Cash dividends declared	(11,580)			0		0		(11,580)			0		0
Stock-based compensation expense	876			0		3,585		0			(2,709)		0
Restricted awards granted	0			0		(2,817)		0			2,817		0
Ending balance at Sep. 30, 2024	$ 741,299			$ 47,619		$ 175,602		$ 835,778			$ (230,836)		$ (86,864)