Loans and Allowance - Credit Quality of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	$ 2,334,716
2020	2,732,120
2019	898,386
2018	437,873
2017	396,281
Prior	691,683
Revolving loans amortized cost basis	1,550,278
Revolving loans converted to term	239
Loans	9,041,576	$ 9,243,174
Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		7,000,298
Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		334,989
Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		234,712
Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,666,062
Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		7,113
PPP loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	182,200
2020	15,900
Loans	198,100	667,100
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	811,829
2020	487,811
2019	194,424
2018	78,731
2017	27,279
Prior	44,221
Revolving loans amortized cost basis	929,320
Revolving loans converted to term	0
Loans	2,573,615	2,776,699
Commercial and industrial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	795,366
2020	458,425
2019	188,155
2018	74,791
2017	24,767
Prior	41,419
Revolving loans amortized cost basis	884,233
Revolving loans converted to term	0
Loans	2,467,156
Commercial and industrial loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	10,551
2020	27,059
2019	211
2018	992
2017	2,032
Prior	2,026
Revolving loans amortized cost basis	17,466
Revolving loans converted to term	0
Loans	60,337
Commercial and industrial loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	5,912
2020	2,327
2019	6,058
2018	2,948
2017	480
Prior	776
Revolving loans amortized cost basis	27,621
Revolving loans converted to term	0
Loans	46,122
Commercial and industrial loans | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,562,077
Commercial and industrial loans | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		117,503
Commercial and industrial loans | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		97,119
Commercial and industrial loans | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial and industrial loans | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial and industrial loans | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial and industrial loans | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Agricultural land, production and other loans to farmers
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	37,803
2020	50,839
2019	23,584
2018	10,950
2017	7,451
Prior	43,191
Revolving loans amortized cost basis	66,868
Revolving loans converted to term	0
Loans	240,686	281,884
Agricultural land, production and other loans to farmers | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	37,000
2020	48,740
2019	23,447
2018	9,152
2017	7,451
Prior	39,875
Revolving loans amortized cost basis	63,254
Revolving loans converted to term	0
Loans	228,919
Agricultural land, production and other loans to farmers | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	84
2020	1,561
2019	0
2018	0
2017	0
Prior	391
Revolving loans amortized cost basis	274
Revolving loans converted to term	0
Loans	2,310
Agricultural land, production and other loans to farmers | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	719
2020	538
2019	137
2018	1,798
2017	0
Prior	2,925
Revolving loans amortized cost basis	3,340
Revolving loans converted to term	0
Loans	9,457
Agricultural land, production and other loans to farmers | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		243,991
Agricultural land, production and other loans to farmers | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		26,835
Agricultural land, production and other loans to farmers | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		9,885
Agricultural land, production and other loans to farmers | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Agricultural land, production and other loans to farmers | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Agricultural land, production and other loans to farmers | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,173
Agricultural land, production and other loans to farmers | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	153,492
2020	202,755
2019	114,065
2018	31,118
2017	2,229
Prior	2,559
Revolving loans amortized cost basis	15,671
Revolving loans converted to term	0
Loans	521,889	484,723
Construction | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	132,653
2020	202,455
2019	114,065
2018	31,056
2017	2,229
Prior	2,559
Revolving loans amortized cost basis	15,671
Revolving loans converted to term
Loans	500,688
Construction | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	20,839
2020	275
2019	0
2018	0
2017	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	21,114
Construction | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	25
2019	0
2018	62
2017	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	87
Construction | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		446,846
Construction | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		10,445
Construction | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		5,549
Construction | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Construction | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Construction | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		21,763
Construction | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		120
Commercial real estate, non-owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	527,316
2020	939,069
2019	229,044
2018	133,851
2017	134,522
Prior	159,889
Revolving loans amortized cost basis	26,696
Revolving loans converted to term	0
Loans	2,150,387	2,220,949
Commercial real estate, non-owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	455,140
2020	740,465
2019	228,864
2018	132,584
2017	127,045
Prior	156,901
Revolving loans amortized cost basis	26,696
Revolving loans converted to term	0
Loans	1,867,695
Commercial real estate, non-owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	52,739
2020	172,621
2019	0
2018	98
2017	0
Prior	2,698
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	228,156
Commercial real estate, non-owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	19,437
2020	25,983
2019	180
2018	1,169
2017	7,477
Prior	290
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	54,536
Commercial real estate, non-owner occupied | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,979,827
Commercial real estate, non-owner occupied | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		160,304
Commercial real estate, non-owner occupied | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		80,818
Commercial real estate, non-owner occupied | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial real estate, non-owner occupied | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial real estate, non-owner occupied | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial real estate, non-owner occupied | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial real estate, owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	224,644
2020	434,040
2019	100,126
2018	47,124
2017	52,213
Prior	61,677
Revolving loans amortized cost basis	32,617
Revolving loans converted to term	0
Loans	952,441	958,501
Commercial real estate, owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	221,409
2020	423,411
2019	99,381
2018	45,467
2017	49,800
Prior	58,497
Revolving loans amortized cost basis	32,468
Revolving loans converted to term	0
Loans	930,433
Commercial real estate, owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	1,548
2020	6,064
2019	745
2018	1,604
2017	0
Prior	1,326
Revolving loans amortized cost basis	149
Revolving loans converted to term	0
Loans	11,436
Commercial real estate, owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	1,687
2020	4,565
2019	0
2018	53
2017	2,413
Prior	1,854
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	10,572
Commercial real estate, owner occupied | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		907,566
Commercial real estate, owner occupied | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		17,641
Commercial real estate, owner occupied | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		33,294
Commercial real estate, owner occupied | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans
Commercial real estate, owner occupied | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans
Commercial real estate, owner occupied | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Commercial real estate, owner occupied | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	265,635
2020	385,523
2019	116,074
2018	81,303
2017	60,736
Prior	240,747
Revolving loans amortized cost basis	4,311
Revolving loans converted to term	44
Loans	1,154,373	1,234,741
Residential | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	263,658
2020	381,258
2019	115,505
2018	80,009
2017	60,398
Prior	235,365
Revolving loans amortized cost basis	4,306
Revolving loans converted to term	44
Loans	1,140,543
Residential | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	874
2020	1,131
2019	464
2018	27
2017	229
Prior	2,200
Revolving loans amortized cost basis	5
Revolving loans converted to term	0
Loans	4,930
Residential | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	1,103
2020	3,134
2019	105
2018	1,267
2017	109
Prior	3,182
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	8,900
Residential | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		199,338
Residential | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,261
Residential | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		7,058
Residential | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Residential | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Residential | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,020,687
Residential | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		5,397
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	68,790
2020	21,560
2019	2,315
2018	2,383
2017	1,513
Prior	4,199
Revolving loans amortized cost basis	430,352
Revolving loans converted to term	195
Loans	531,307	508,259
Home equity | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	68,318
2020	21,473
2019	2,315
2018	2,374
2017	1,419
Prior	3,982
Revolving loans amortized cost basis	427,901
Revolving loans converted to term	195
Loans	527,977
Home equity | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	87
2019	0
2018	9
2017	0
Prior	17
Revolving loans amortized cost basis	1,378
Revolving loans converted to term	0
Loans	1,491
Home equity | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	472
2020	0
2019	0
2018	0
2017	94
Prior	200
Revolving loans amortized cost basis	1,073
Revolving loans converted to term	0
Loans	1,839
Home equity | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		12,714
Home equity | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Home equity | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		989
Home equity | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Home equity | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Home equity | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		492,999
Home equity | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,557
Individuals' loans for household and other personal expenditures
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	41,398
2020	30,610
2019	17,862
2018	13,177
2017	2,664
Prior	5,712
Revolving loans amortized cost basis	23,670
Revolving loans converted to term	0
Loans	135,093	129,479
Individuals' loans for household and other personal expenditures | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	41,367
2020	30,506
2019	17,797
2018	13,132
2017	2,657
Prior	5,684
Revolving loans amortized cost basis	23,659
Revolving loans converted to term	0
Loans	134,802
Individuals' loans for household and other personal expenditures | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	31
2020	101
2019	65
2018	45
2017	7
Prior	15
Revolving loans amortized cost basis	11
Revolving loans converted to term	0
Loans	275
Individuals' loans for household and other personal expenditures | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	3
2019	0
2018	0
2017	0
Prior	13
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	16
Individuals' loans for household and other personal expenditures | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Individuals' loans for household and other personal expenditures | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Individuals' loans for household and other personal expenditures | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Individuals' loans for household and other personal expenditures | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Individuals' loans for household and other personal expenditures | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Individuals' loans for household and other personal expenditures | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		129,440
Individuals' loans for household and other personal expenditures | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		39
Public finance and other commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	203,809
2020	179,913
2019	100,892
2018	39,236
2017	107,674
Prior	129,488
Revolving loans amortized cost basis	20,773
Revolving loans converted to term	0
Loans	781,785	647,939
Public finance and other commercial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	203,809
2020	179,913
2019	100,892
2018	39,236
2017	107,674
Prior	129,488
Revolving loans amortized cost basis	20,773
Revolving loans converted to term	0
Loans	$ 781,785
Public finance and other commercial loans | Commercial Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		647,939
Public finance and other commercial loans | Commercial Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Public finance and other commercial loans | Commercial Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Public finance and other commercial loans | Commercial Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Public finance and other commercial loans | Commercial Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Public finance and other commercial loans | Consumer Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		0
Public finance and other commercial loans | Consumer Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 0