Basis of Presentation and Significant Accounting Policies, Pre-tax Impact Adoption of ASU (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Jan. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	$ (61,032)	$ (61,007)	$ (61,007)	$ (60,175)	$ (58,862)
Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(43,047)	(41,149)	(42,452)
Commercial Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(17,920)	(17,379)	(28,536)
Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(14,591)	(14,580)	(9,613)
Residential and Home Equity [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(6,759)	(5,879)	(2,847)	(2,881)	(2,984)
Construction [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(3,777)	(3,311)	(1,456)	(1,647)	(1,643)
Commercial and Industrial [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(10,361)	(11,417)	(11,489)
Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(5,737)	(6,363)	(5,465)
Commercial Leases [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	(1,466)	(1,567)	(938)	(1,674)	(1,731)
Consumer and Other [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses	$ (421)	(511)	$ (663)	$ (1,636)	$ (1,417)
Reported Pre-Adoption [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(61,007)
Reported Pre-Adoption [Member] | Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(42,452)
Reported Pre-Adoption [Member] | Commercial Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(28,536)
Reported Pre-Adoption [Member] | Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(9,613)
Reported Pre-Adoption [Member] | Residential and Home Equity [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(2,847)
Reported Pre-Adoption [Member] | Construction [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(1,456)
Reported Pre-Adoption [Member] | Commercial and Industrial [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(11,489)
Reported Pre-Adoption [Member] | Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(5,465)
Reported Pre-Adoption [Member] | Commercial Leases [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(938)
Reported Pre-Adoption [Member] | Consumer and Other [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(663)
Impact of ASC 326 Adoption [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		0
Impact of ASC 326 Adoption [Member] | Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		1,303
Impact of ASC 326 Adoption [Member] | Commercial Real Estate [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		11,157
Impact of ASC 326 Adoption [Member] | Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(4,967)
Impact of ASC 326 Adoption [Member] | Residential and Home Equity [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(3,032)
Impact of ASC 326 Adoption [Member] | Construction [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(1,855)
Impact of ASC 326 Adoption [Member] | Commercial and Industrial [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		72
Impact of ASC 326 Adoption [Member] | Agricultural [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(898)
Impact of ASC 326 Adoption [Member] | Commercial Leases [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		(629)
Impact of ASC 326 Adoption [Member] | Consumer and Other [Member]
Pre-tax Impact of Adoption of ASU [Abstract]
Allowance for credit losses		$ 152