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Loans - Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2022 | Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | $ 5,528,093 | $ 5,231,331
Real estate | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 452,645 | 558,263
Year two | 513,445 | 369,753
Year three | 292,684 | 278,817
Year four | 255,563 | 247,391
Year five | 190,736 | 127,435
Prior | 182,514 | 88,786
Revolving Loans Amortized Cost Basis | 21,467 | 23,067
Total | 1,909,054 | 1,693,512
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 0 | 0
2020, Current period gross charge-offs | 0 | 0
2019, Current period gross charge-offs | 0 | 0
2018, Current period gross charge-offs | 0 | 120
2017, Current period gross charge-offs |  | 24
Prior, Current period gross charge-offs | 166 | 26
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 0 | 0
Charge-offs | 166 | 170
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 0 | 0
2019, Current period gross recoveries | 0 | 0
2018, Current period gross recoveries | 0 | 48
2017, Current period gross recoveries |  | 3
Prior, Current period gross recoveries | 2 | 14
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 0 | 0
Total, Current period gross recoveries | 2 | 65
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 0 | 0
2020, Current period net charge-offs (recoveries) | 0 | 0
2019, Current period net charge-offs (recoveries) | 0 | 0
2018, Current period net charge-offs (recoveries) | 0 | 72
2017 Current period net charge-offs (recoveries) |  | 21
Prior, Current period net charge-offs (recoveries) | 164 | 12
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 0 | 0
Total, Current period net charge-offs (recoveries) | 164 | 105
Real estate | Commercial real estate | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 452,645 | 556,218
Year two | 511,619 | 369,128
Year three | 292,129 | 278,045
Year four | 250,980 | 236,543
Year five | 180,073 | 111,308
Prior | 168,953 | 86,498
Revolving Loans Amortized Cost Basis | 21,304 | 22,904
Total | 1,877,703 | 1,660,644
Real estate | Commercial real estate | Special mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 0 | 0
Year two | 0 | 0
Year three | 0 | 0
Year four | 3,866 | 8,392
Year five | 8,293 | 15,828
Prior | 1,405 | 0
Revolving Loans Amortized Cost Basis | 0 | 0
Total | 13,564 | 24,220
Real estate | Commercial real estate | Classified |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 0 | 2,045
Year two | 1,826 | 625
Year three | 555 | 772
Year four | 717 | 2,456
Year five | 2,370 | 299
Prior | 12,156 | 2,288
Revolving Loans Amortized Cost Basis | 163 | 163
Total | 17,787 | 8,648
Real estate | Construction/land/land development |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 156,309 | 256,655
Year two | 288,958 | 102,756
Year three | 67,790 | 93,840
Year four | 50,937 | 33,805
Year five | 27,856 | 6,583
Prior | 5,729 | 553
Revolving Loans Amortized Cost Basis | 37,977 | 35,891
Total | 635,556 | 530,083
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 0 | 0
2020, Current period gross charge-offs | 0 | 0
2019, Current period gross charge-offs | 0 | 0
2018, Current period gross charge-offs | 0 | 0
2017, Current period gross charge-offs |  | 0
Prior, Current period gross charge-offs | 0 | 0
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 0 | 0
Charge-offs | 0 | 0
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 0 | 0
2019, Current period gross recoveries | 0 | 0
2018, Current period gross recoveries | 0 | 0
2017, Current period gross recoveries |  | 0
Prior, Current period gross recoveries | 0 | 0
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 0 | 0
Total, Current period gross recoveries | 0 | 0
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 0 | 0
2020, Current period net charge-offs (recoveries) | 0 | 0
2019, Current period net charge-offs (recoveries) | 0 | 0
2018, Current period net charge-offs (recoveries) | 0 | 0
2017 Current period net charge-offs (recoveries) |  | 0
Prior, Current period net charge-offs (recoveries) | 0 | 0
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 0 | 0
Total, Current period net charge-offs (recoveries) | 0 | 0
Real estate | Construction/land/land development | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 156,136 | 256,212
Year two | 288,817 | 102,459
Year three | 67,507 | 85,442
Year four | 50,777 | 32,128
Year five | 27,686 | 5,422
Prior | 4,008 | 553
Revolving Loans Amortized Cost Basis | 37,833 | 30,729
Total | 632,764 | 512,945
Real estate | Construction/land/land development | Special mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one |  | 0
Year two |  | 0
Year three |  | 8,126
Year four |  | 0
Year five |  | 1,003
Prior |  | 0
Revolving Loans Amortized Cost Basis |  | 0
Total |  | 9,129
Real estate | Construction/land/land development | Classified |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 173 | 443
Year two | 141 | 297
Year three | 283 | 272
Year four | 160 | 1,677
Year five | 170 | 158
Prior | 1,721 | 0
Revolving Loans Amortized Cost Basis | 144 | 5,162
Total | 2,792 | 8,009
Real estate | Residential real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 214,908 | 315,296
Year two | 255,864 | 252,480
Year three | 236,598 | 111,957
Year four | 98,545 | 55,784
Year five | 42,103 | 47,338
Prior | 94,512 | 66,296
Revolving Loans Amortized Cost Basis | 63,093 | 60,588
Total | 1,005,623 | 909,739
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 0 | 0
2020, Current period gross charge-offs | 0 | 7
2019, Current period gross charge-offs | 0 | 61
2018, Current period gross charge-offs | 0 | 0
2017, Current period gross charge-offs |  | 0
Prior, Current period gross charge-offs | 75 | 10
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 0 | 0
Charge-offs | 75 | 78
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 0 | 21
2019, Current period gross recoveries | 75 | 19
2018, Current period gross recoveries | 0 | 0
2017, Current period gross recoveries |  | 25
Prior, Current period gross recoveries | 17 | 52
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 0 | 0
Total, Current period gross recoveries | 92 | 117
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 0 | 0
2020, Current period net charge-offs (recoveries) | 0 | (14)
2019, Current period net charge-offs (recoveries) | (75) | 42
2018, Current period net charge-offs (recoveries) | 0 | 0
2017 Current period net charge-offs (recoveries) |  | (25)
Prior, Current period net charge-offs (recoveries) | 58 | (42)
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 0 | 0
Total, Current period net charge-offs (recoveries) | (17) | (39)
Real estate | Residential real estate | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 214,417 | 313,898
Year two | 255,510 | 252,115
Year three | 236,331 | 109,564
Year four | 97,282 | 52,515
Year five | 41,029 | 45,042
Prior | 88,613 | 59,690
Revolving Loans Amortized Cost Basis | 62,790 | 60,342
Total | 995,972 | 893,166
Real estate | Residential real estate | Special mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 0 | 0
Year two | 0 | 174
Year three | 166 | 0
Year four | 0 | 421
Year five | 0 | 477
Prior | 0 | 0
Revolving Loans Amortized Cost Basis | 0 | 0
Total | 166 | 1,072
Real estate | Residential real estate | Classified |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 491 | 1,398
Year two | 354 | 191
Year three | 101 | 2,393
Year four | 1,263 | 2,848
Year five | 1,074 | 1,819
Prior | 5,899 | 6,606
Revolving Loans Amortized Cost Basis | 303 | 246
Total | 9,485 | 15,501
Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 191,072 | 463,014
Year two | 312,668 | 167,247
Year three | 107,595 | 96,466
Year four | 73,758 | 70,159
Year five | 43,609 | 18,591
Prior | 37,103 | 27,022
Revolving Loans Amortized Cost Basis | 664,434 | 611,736
Total | 1,430,239 | 1,454,235
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 724 | 9
2020, Current period gross charge-offs | 0 | 1,172
2019, Current period gross charge-offs | 865 | 54
2018, Current period gross charge-offs | 337 | 5
2017, Current period gross charge-offs |  | 1,467
Prior, Current period gross charge-offs | 301 | 6,354
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 2,098 | 2,862
Charge-offs | 4,325 | 11,923
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 0 | 18
2019, Current period gross recoveries | 34 | 51
2018, Current period gross recoveries | 15 | 3
2017, Current period gross recoveries |  | 102
Prior, Current period gross recoveries | 246 | 204
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 885 | 339
Total, Current period gross recoveries | 1,180 | 717
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 724 | 9
2020, Current period net charge-offs (recoveries) | 0 | 1,154
2019, Current period net charge-offs (recoveries) | 831 | 3
2018, Current period net charge-offs (recoveries) | 322 | 2
2017 Current period net charge-offs (recoveries) |  | 1,365
Prior, Current period net charge-offs (recoveries) | 55 | 6,150
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 1,213 | 2,523
Total, Current period net charge-offs (recoveries) | 3,145 | 11,206
Commercial and industrial | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 189,363 | 448,377
Year two | 302,510 | 164,910
Year three | 107,423 | 93,488
Year four | 72,345 | 64,791
Year five | 42,027 | 14,742
Prior | 33,751 | 24,014
Revolving Loans Amortized Cost Basis | 660,486 | 599,144
Total | 1,407,905 | 1,409,466
Commercial and industrial | Special mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 150 | 259
Year two | 62 | 2,170
Year three | 0 | 0
Year four | 0 | 1,519
Year five | 192 | 0
Prior | 0 | 0
Revolving Loans Amortized Cost Basis | 0 | 3,752
Total | 404 | 7,700
Commercial and industrial | Classified |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 1,559 | 14,378
Year two | 10,096 | 167
Year three | 172 | 2,978
Year four | 1,413 | 3,849
Year five | 1,390 | 3,849
Prior | 3,352 | 3,008
Revolving Loans Amortized Cost Basis | 3,948 | 8,840
Total | 21,930 | 37,069
Mortgage warehouse lines of credit |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 531,888 | 627,078
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 0 | 0
2020, Current period gross charge-offs | 0 | 0
2019, Current period gross charge-offs | 0 | 0
2018, Current period gross charge-offs | 0 | 0
2017, Current period gross charge-offs |  | 0
Prior, Current period gross charge-offs | 0 | 0
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 0 | 0
Charge-offs | 0 | 0
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 0 | 0
2019, Current period gross recoveries | 0 | 0
2018, Current period gross recoveries | 0 | 0
2017, Current period gross recoveries |  | 0
Prior, Current period gross recoveries | 0 | 0
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 0 | 0
Total, Current period gross recoveries | 0 | 0
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 0 | 0
2020, Current period net charge-offs (recoveries) | 0 | 0
2019, Current period net charge-offs (recoveries) | 0 | 0
2018, Current period net charge-offs (recoveries) | 0 | 0
2017 Current period net charge-offs (recoveries) |  | 0
Prior, Current period net charge-offs (recoveries) | 0 | 0
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 0 | 0
Total, Current period net charge-offs (recoveries) | 0 | 0
Mortgage warehouse lines of credit | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 0 | 0
Year two | 0 | 0
Year three | 0 | 0
Year four | 0 | 0
Year five | 0 | 0
Prior | 0 | 0
Revolving Loans Amortized Cost Basis | 531,888 | 627,078
Total | 531,888 | 627,078
Consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 3,779 | 7,002
Year two | 4,546 | 2,190
Year three | 1,393 | 1,468
Year four | 969 | 443
Year five | 238 | 55
Prior | 49 | 68
Revolving Loans Amortized Cost Basis | 4,759 | 5,458
Total | 15,733 | 16,684
2022, Current period gross charge-offs | 0 |
2021, Current period gross charge-offs | 20 | 0
2020, Current period gross charge-offs | 6 | 5
2019, Current period gross charge-offs | 0 | 29
2018, Current period gross charge-offs | 1 | 2
2017, Current period gross charge-offs |  | 0
Prior, Current period gross charge-offs | 1 | 9
Revolving Loans Amortized Cost Basis, Current period gross charge-offs | 0 | 18
Charge-offs | 28 | 63
2022, Current period gross recoveries | 0 |
2021, Current period gross recoveries | 0 | 0
2020, Current period gross recoveries | 7 | 0
2019, Current period gross recoveries | 0 | 20
2018, Current period gross recoveries | 1 | 7
2017, Current period gross recoveries |  | 1
Prior, Current period gross recoveries | 5 | 17
Revolving Loans Amortized Cost Basis, Current period gross recoveries | 0 | 4
Total, Current period gross recoveries | 13 | 49
2022, Current period net charge-offs (recoveries) | 0 |
2021, Current period net charge-offs (recoveries) | 20 | 0
2020, Current period net charge-offs (recoveries) | (1) | 5
2019, Current period net charge-offs (recoveries) | 0 | 9
2018, Current period net charge-offs (recoveries) | 0 | (5)
2017 Current period net charge-offs (recoveries) |  | (1)
Prior, Current period net charge-offs (recoveries) | (4) | (8)
Revolving Loans Amortized Cost Basis, Current period net charge-offs (recoveries) | 0 | 14
Total, Current period net charge-offs (recoveries) | 15 | 14
Consumer | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 3,774 | 6,976
Year two | 4,527 | 2,169
Year three | 1,393 | 1,467
Year four | 961 | 443
Year five | 238 | 55
Prior | 49 | 67
Revolving Loans Amortized Cost Basis | 4,711 | 5,407
Total | 15,653 | 16,584
Consumer | Classified |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Year one | 5 | 26
Year two | 19 | 21
Year three | 0 | 1
Year four | 8 | 0
Year five | 0 | 0
Prior | 0 | 1
Revolving Loans Amortized Cost Basis | 48 | 51
Total | $ 80 | $ 100

X
- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated Five Or More Years Before Latest Fiscal Year + References No definition available. + Details
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Period Type: | duration

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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated Five Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated Four Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated in Current Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated Three Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Originated Two Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Recovery, Revolving + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated Five Or More Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated Five Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated Four Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated in Current Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated Three Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Originated Two Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, After Recovery, Revolving + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated Five Or More Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated Five Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated Four Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated in Current Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated Three Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Originated Two Years Before Latest Fiscal Year + References No definition available. + Details
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- Definition Financing Receivable, Allowance For Credit Loss, Writeoff, Revolving + References No definition available. + Details
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Namespace Prefix: | obnk_
Data Type: | xbrli:monetaryItemType
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Period Type: | duration

X
- Definition Financing Receivable Excluding Loans At Fair Value, Before Allowance for Credit Loss + References No definition available. + Details
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Namespace Prefix: | obnk_
Data Type: | xbrli:monetaryItemType
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