Loans and Allowance - Credit Quality of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	$ 1,762,033
2020	3,113,823
2019	1,054,421
2018	543,522
2017	429,625
Prior	789,175
Revolving loans amortized cost basis	1,428,446
Revolving loans converted to term	205
Loans	9,121,250	$ 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	302,000
2020	113,800
Loans	415,800	667,100
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	716,339
2020	715,128
2019	227,245
2018	90,802
2017	37,661
Prior	64,562
Revolving loans amortized cost basis	819,339
Revolving loans converted to term	0
Loans	2,671,076	2,776,699
Commercial and industrial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	705,017
2020	680,616
2019	220,134
2018	88,941
2017	35,001
Prior	61,402
Revolving loans amortized cost basis	764,492
Revolving loans converted to term	0
Loans	2,555,603
Commercial and industrial loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	8,826
2020	31,372
2019	963
2018	1,214
2017	2,315
Prior	2,299
Revolving loans amortized cost basis	17,494
Revolving loans converted to term	0
Loans	64,483
Commercial and industrial loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	2,496
2020	3,140
2019	6,148
2018	647
2017	345
Prior	861
Revolving loans amortized cost basis	37,353
Revolving loans converted to term	0
Loans	50,990
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	30,158
2020	56,631
2019	24,737
2018	12,653
2017	7,693
Prior	47,297
Revolving loans amortized cost basis	55,851
Revolving loans converted to term	0
Loans	235,020	281,884
Agricultural land, production and other loans to farmers | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	29,307
2020	53,177
2019	24,414
2018	10,441
2017	7,291
Prior	43,426
Revolving loans amortized cost basis	50,668
Revolving loans converted to term	0
Loans	218,724
Agricultural land, production and other loans to farmers | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	132
2020	1,561
2019	186
2018	480
2017	0
Prior	392
Revolving loans amortized cost basis	1,572
Revolving loans converted to term	0
Loans	4,323
Agricultural land, production and other loans to farmers | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	719
2020	1,893
2019	137
2018	1,732
2017	402
Prior	3,479
Revolving loans amortized cost basis	3,611
Revolving loans converted to term	0
Loans	11,973
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	87,073
2020	190,757
2019	140,397
2018	49,491
2017	3,031
Prior	2,789
Revolving loans amortized cost basis	17,662
Revolving loans converted to term	0
Loans	491,200	484,723
Construction | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	87,073
2020	190,362
2019	140,397
2018	49,429
2017	3,031
Prior	2,788
Revolving loans amortized cost basis	17,622
Revolving loans converted to term
Loans	490,702
Construction | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	367
2019	0
2018	0
2017	0
Prior	0
Revolving loans amortized cost basis	40
Revolving loans converted to term	0
Loans	407
Construction | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	28
2019	0
2018	62
2017	0
Prior	1
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	91
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	379,924
2020	1,029,928
2019	299,706
2018	193,952
2017	142,072
Prior	187,897
Revolving loans amortized cost basis	30,018
Revolving loans converted to term	0
Loans	2,263,497	2,220,949
Commercial real estate, non-owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	320,351
2020	829,716
2019	276,030
2018	181,489
2017	134,569
Prior	177,499
Revolving loans amortized cost basis	28,768
Revolving loans converted to term	0
Loans	1,948,422
Commercial real estate, non-owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	53,576
2020	161,095
2019	0
2018	10,333
2017	0
Prior	10,098
Revolving loans amortized cost basis	1,250
Revolving loans converted to term	0
Loans	236,352
Commercial real estate, non-owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	5,997
2020	39,117
2019	23,676
2018	2,130
2017	7,503
Prior	300
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	78,723
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	155,906
2020	461,527
2019	113,066
2018	50,488
2017	58,035
Prior	78,733
Revolving loans amortized cost basis	35,746
Revolving loans converted to term	0
Loans	953,501	958,501
Commercial real estate, owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	154,390
2020	444,147
2019	110,496
2018	48,809
2017	53,093
Prior	75,210
Revolving loans amortized cost basis	35,589
Revolving loans converted to term	0
Loans	921,734
Commercial real estate, owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	562
2020	5,813
2019	2,570
2018	1,626
2017	2,208
Prior	1,748
Revolving loans amortized cost basis	157
Revolving loans converted to term	0
Loans	14,684
Commercial real estate, owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	954
2020	11,567
2019	0
2018	53
2017	2,734
Prior	1,775
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	17,083
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	164,340
2020	415,586
2019	124,703
2018	88,165
2017	67,304
Prior	263,302
Revolving loans amortized cost basis	4,008
Revolving loans converted to term	34
Loans	1,127,442	1,234,741
Residential | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	162,624
2020	411,016
2019	124,377
2018	86,116
2017	67,041
Prior	258,010
Revolving loans amortized cost basis	3,919
Revolving loans converted to term	34
Loans	1,113,137
Residential | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	282
2020	1,322
2019	219
2018	657
2017	60
Prior	1,152
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	3,692
Residential | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	1,434
2020	3,248
2019	107
2018	1,392
2017	203
Prior	4,140
Revolving loans amortized cost basis	89
Revolving loans converted to term	0
Loans	10,613
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	24,632
2020	20,741
2019	2,313
2018	2,549
2017	1,703
Prior	4,926
Revolving loans amortized cost basis	432,962
Revolving loans converted to term	171
Loans	489,997	508,259
Home equity | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	24,144
2020	20,741
2019	2,313
2018	2,530
2017	1,605
Prior	4,689
Revolving loans amortized cost basis	430,070
Revolving loans converted to term	171
Loans	486,263
Home equity | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	0
2019	0
2018	9
2017	0
Prior	59
Revolving loans amortized cost basis	1,888
Revolving loans converted to term	0
Loans	1,956
Home equity | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	488
2020	0
2019	0
2018	10
2017	98
Prior	178
Revolving loans amortized cost basis	1,004
Revolving loans converted to term	0
Loans	1,778
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	31,107
2020	34,435
2019	20,736
2018	15,747
2017	3,449
Prior	6,383
Revolving loans amortized cost basis	18,962
Revolving loans converted to term	0
Loans	130,819	129,479
Individuals' loans for household and other personal expenditures | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	31,102
2020	34,212
2019	20,548
2018	15,707
2017	3,433
Prior	6,358
Revolving loans amortized cost basis	17,855
Revolving loans converted to term	0
Loans	129,215
Individuals' loans for household and other personal expenditures | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	5
2020	223
2019	188
2018	40
2017	16
Prior	25
Revolving loans amortized cost basis	1,107
Revolving loans converted to term	0
Loans	1,604
Individuals' loans for household and other personal expenditures | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Loans	0
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	172,554
2020	189,090
2019	101,518
2018	39,675
2017	108,677
Prior	133,286
Revolving loans amortized cost basis	13,898
Revolving loans converted to term	0
Loans	758,698	647,939
Public finance and other commercial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	172,554
2020	189,090
2019	101,518
2018	39,675
2017	108,677
Prior	133,286
Revolving loans amortized cost basis	13,898
Revolving loans converted to term	0
Loans	$ 758,698
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