Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($)	Total	LINCO Bancshares, Inc.	Blackhawk Bancorp, Inc	Common Stock	Common Stock LINCO Bancshares, Inc.	Common Stock Blackhawk Bancorp, Inc	Additional Paid-in Capital	Additional Paid-in Capital LINCO Bancshares, Inc.	Additional Paid-in Capital Blackhawk Bancorp, Inc	Retained Earnings	Deferred Compensation	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2021	$ 633,894,000			$ 76,835,000			$ 340,419,000			$ 234,162,000	$ 2,517,000	$ (831,000)	$ (19,208,000)
Net Income (Loss)	52,313,000									52,313,000
Other comprehensive Income (loss), net tax	(166,832,000)											(166,832,000)
Cash dividends on common stock	(13,140,000)									(13,140,000)
Issuance of common shares pursuant to the deferred compensation plan	331,000			34,000			297,000
Issuance of restricted shares pursuant to the stock incentive plan	2,250,000			218,000			2,032,000
Issuance of common shares pursuant to 2017 stock incentive plan	199,000			20,000			179,000
Issuance of common shares pursuant to the employee stock purchase plan	478,000			58,000			420,000
Issuance of shares pursuant to the acquisition		$ 92,172,000			$ 9,169,000			$ 83,003,000
Issuance costs pursuant to acquisition of Delta Bancshares Company	(29,000)						(29,000)
Purchase of shares of treasury stock	(11,000)												(11,000)
Deferred compensation	(2,563,000)										(2,206,000)		(357,000)
Grant of restricted units pursuant to 2017 stock incentive plan	1,529,000						1,529,000
Release of restricted units pursuant to 2017 stock incentive plan	(1,216,000)						(1,216,000)
Vested restricted shares/units compensation expense	1,340,000						133,000				1,207,000
Ending balance at Sep. 30, 2022	600,715,000			86,334,000			426,767,000			273,335,000	1,518,000	(167,663,000)	(19,576,000)
Beginning balance at Jun. 30, 2022	626,268,000			86,310,000			426,562,000			260,080,000	974,000	(128,240,000)	(19,418,000)
Net Income (Loss)	17,939,000									17,939,000
Other comprehensive Income (loss), net tax	(39,423,000)											(39,423,000)
Cash dividends on common stock	(4,684,000)									(4,684,000)
Issuance of common shares pursuant to the deferred compensation plan	(9,000)			(1,000)			(8,000)
Issuance of common shares pursuant to the employee stock purchase plan	185,000			25,000			160,000
Deferred compensation	(8,000)										166,000		(158,000)
Vested restricted shares/units compensation expense	431,000						53,000				378,000
Ending balance at Sep. 30, 2022	600,715,000			86,334,000			426,767,000			273,335,000	1,518,000	(167,663,000)	(19,576,000)
Beginning balance at Dec. 31, 2022	633,155,000			86,366,000			427,001,000			289,284,000	2,064,000	(151,507,000)	(20,053,000)
Net Income (Loss)	50,864,000									50,864,000
Other comprehensive Income (loss), net tax	(27,396,000)											(27,396,000)
Cash dividends on common stock	(14,096,000)									(14,096,000)
Issuance of restricted shares pursuant to the stock incentive plan, net of forfeitures	1,622,000			218,000			1,404,000
Issuance of common shares pursuant to 2017 stock incentive plan	120,000			17,000			103,000
Issuance of common shares pursuant to the employee stock purchase plan	667,000			115,000			552,000
Issuance of shares pursuant to the acquisition			$ 93,508,000			$ 13,161,000			$ 80,347,000
Purchase of shares of treasury stock	(5,000)												(5,000)
Deferred compensation	(1,223,000)										(1,036,000)		(187,000)
Grant of restricted units pursuant to 2017 stock incentive plan	1,048,000						1,048,000
Release of restricted units pursuant to 2017 stock incentive plan	(1,529,000)						(1,529,000)
Vested restricted shares/units compensation expense	1,213,000						169,000				1,044,000
Ending balance at Sep. 30, 2023	737,948,000			99,877,000			509,095,000			326,052,000	2,072,000	(178,903,000)	(20,245,000)
Beginning balance at Jun. 30, 2023	660,687,000			86,670,000			428,504,000			315,636,000	1,502,000	(151,566,000)	(20,059,000)
Net Income (Loss)	15,117,000									15,117,000
Other comprehensive Income (loss), net tax	(27,337,000)											(27,337,000)
Cash dividends on common stock	(4,701,000)									(4,701,000)
Issuance of common shares pursuant to the employee stock purchase plan	238,000			46,000			192,000
Issuance of shares pursuant to the acquisition			$ 93,508,000			$ 13,161,000			$ 80,347,000
Deferred compensation	(33,000)										153,000		(186,000)
Vested restricted shares/units compensation expense	469,000						52,000				417,000
Ending balance at Sep. 30, 2023	$ 737,948,000			$ 99,877,000			$ 509,095,000			$ 326,052,000	$ 2,072,000	$ (178,903,000)	$ (20,245,000)