Loans (Analysis of the Aged Loan Portfolio) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 11,610,973	$ 10,641,937
Nonaccrual Loans	13,441	23,041
Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,352,785	4,981,263
Nonaccrual Loans	3,244	1,872
Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,750,564	3,423,268
Nonaccrual Loans	5,133	13,321
Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	848,903	795,715
Nonaccrual Loans	4,367	5,396
Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	540,861	384,755
Nonaccrual Loans	0	0
Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,077,494	1,013,908
Nonaccrual Loans	685	2,433
Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	40,366	43,028
Nonaccrual Loans	12	19
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	11,574,480	10,611,528
Financial Asset, Not Past Due | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,338,999	4,977,781
Financial Asset, Not Past Due | Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,739,731	3,406,539
Financial Asset, Not Past Due | Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	842,506	789,112
Financial Asset, Not Past Due | Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	540,861	384,755
Financial Asset, Not Past Due | Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,072,211	1,010,343
Financial Asset, Not Past Due | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	40,172	42,998
Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	16,060	4,860
Financial Asset, 30 to 59 Days Past Due | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,756	0
Financial Asset, 30 to 59 Days Past Due | Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,336	2,721
Financial Asset, 30 to 59 Days Past Due | Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	493	1,207
Financial Asset, 30 to 59 Days Past Due | Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 30 to 59 Days Past Due | Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,315	921
Financial Asset, 30 to 59 Days Past Due | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	160	11
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,992	2,508
Financial Asset, 60 to 89 Days Past Due | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,786	1,610
Financial Asset, 60 to 89 Days Past Due | Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,364	687
Financial Asset, 60 to 89 Days Past Due | Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,537	0
Financial Asset, 60 to 89 Days Past Due | Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due | Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	283	211
Financial Asset, 60 to 89 Days Past Due | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	22	0
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	23,052	7,368
Financial Asset, Past Due | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,542	1,610
Financial Asset, Past Due | Commercial Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,700	3,408
Financial Asset, Past Due | Agriculture
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,030	1,207
Financial Asset, Past Due | Construction
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Past Due | Real estate: One-to-four family residential
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,598	1,132
Financial Asset, Past Due | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 182	$ 11