Loans and Leases, Components of Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Loan & Lease Portfolio [Abstract]
Gross loans and leases	$ 3,706,437	$ 3,665,397
Unearned income	(10,142)	(10,708)
Total net loans and leases	3,696,295	3,654,689
Allowance for credit losses	(75,018)	(74,965)	$ (66,885)
Loans and leases held for investment, net	3,621,277	3,579,724
Remaining borrowing capacity	1,900,000	2,200,000
Federal Home Loan Bank [Member]
Loan & Lease Portfolio [Abstract]
Collateral amount	1,300,000
Remaining borrowing capacity	767,700
Federal Reserve Bank [Member]
Loan & Lease Portfolio [Abstract]
Collateral amount	1,600,000
Remaining borrowing capacity	1,200,000
Real Estate [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	2,710,996	2,677,391
Total net loans and leases	2,703,362	2,669,281
Allowance for credit losses	(46,128)	(46,039)
Commercial [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	1,352,014	1,323,038
Total net loans and leases	1,344,380	1,314,928
Allowance for credit losses	(22,414)	(26,093)
Agricultural [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	726,041	742,009
Total net loans and leases	726,041	742,009
Allowance for credit losses	(11,377)	(7,744)
Residential and Home Equity [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	405,526	399,982
Total net loans and leases	405,526	399,982
Allowance for credit losses	(7,721)	(7,770)	(7,508)
Construction [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	227,415	212,362
Total net loans and leases	227,415	212,362
Allowance for credit losses	(4,616)	(4,432)	(3,026)
Commercial & Industrial [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	497,028	499,373
Total net loans and leases	497,028	499,373
Allowance for credit losses	(11,559)	(13,380)
Agricultural [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	317,955	313,737
Total net loans and leases	317,955	313,737
Allowance for credit losses	(10,292)	(8,872)
Commercial Leases [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	174,657	169,684
Total net loans and leases	172,149	167,086
Allowance for credit losses	(6,923)	(6,537)	(1,924)
Consumer and Other [Member]
Loan & Lease Portfolio [Abstract]
Gross loans and leases	5,801	5,212
Total net loans and leases	5,801	5,212
Allowance for credit losses	$ (116)	$ (137)	$ (171)

Amount of assets pledged to secure a debt instrument.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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