XML 51 R41.htm IDEA: XBRL DOCUMENT
v3.19.1

Loans and ALLL (Credit quality indicators for commercial and agricultural credit exposures) (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Financing Receivable, Recorded Investment [Line Items] |  |
Total | $ 1,144,832 | $ 1,128,707
Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 677,554 | 659,529
Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 499,476 | 497,687
Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 153,483 | 150,049
Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 24,595 | 11,793
Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 123,393 | 127,161
Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 85,917 | 87,320
Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 37,476 | 39,841
Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 800,947 | 786,690
1 - Excellent [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 52
1 - Excellent [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 21
1 - Excellent [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 31
1 - Excellent [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
1 - Excellent [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 79
1 - Excellent [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 51
1 - Excellent [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 28
1 - Excellent [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 131
2 - High quality [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 16,741 | 18,037
2 - High quality [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 4,351 | 4,564
2 - High quality [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 12,390 | 13,473
2 - High quality [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
2 - High quality [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 2,980 | 3,342
2 - High quality [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 2,510 | 2,729
2 - High quality [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 470 | 613
2 - High quality [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 19,721 | 21,379
3 - High satisfactory [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 191,878 | 182,565
3 - High satisfactory [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 123,161 | 127,573
3 - High satisfactory [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 44,122 | 43,199
3 - High satisfactory [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 24,595 | 11,793
3 - High satisfactory [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 23,810 | 25,364
3 - High satisfactory [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 17,934 | 18,325
3 - High satisfactory [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 5,876 | 7,039
3 - High satisfactory [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 215,688 | 207,929
4 - Low satisfactory [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 438,882 | 429,554
4 - Low satisfactory [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 349,430 | 344,920
4 - Low satisfactory [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 89,452 | 84,634
4 - Low satisfactory [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
4 - Low satisfactory [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 64,213 | 65,980
4 - Low satisfactory [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 45,517 | 46,636
4 - Low satisfactory [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 18,696 | 19,344
4 - Low satisfactory [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 503,095 | 495,534
5 - Special mention [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 22,607 | 18,134
5 - Special mention [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 16,947 | 12,847
5 - Special mention [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 5,660 | 5,287
5 - Special mention [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
5 - Special mention [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 14,987 | 16,144
5 - Special mention [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 9,726 | 10,520
5 - Special mention [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 5,261 | 5,624
5 - Special mention [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 37,594 | 34,278
6 - Substandard [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 5,515 | 9,430
6 - Substandard [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 4,898 | 7,428
6 - Substandard [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 617 | 2,002
6 - Substandard [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
6 - Substandard [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 12,646 | 11,303
6 - Substandard [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 7,576 | 6,343
6 - Substandard [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 5,070 | 4,960
6 - Substandard [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 18,161 | 20,733
7 - Vulnerable [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 1,931 | 1,757
7 - Vulnerable [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 689 | 334
7 - Vulnerable [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 1,242 | 1,423
7 - Vulnerable [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
7 - Vulnerable [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 4,757 | 4,949
7 - Vulnerable [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 2,654 | 2,716
7 - Vulnerable [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 2,103 | 2,233
7 - Vulnerable [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 6,688 | 6,706
8 - Doubtful [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
8 - Doubtful [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Total commercial [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Commercial real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Commercial other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Commercial Advances to Mortgage Brokers Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Total agricultural [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Agricultural real estate [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Agricultural other [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | 0 | 0
Loss [Member] | Commercial And Agricultural Portfolio Segment [Member] |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total | $ 0 | $ 0

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(3)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_CommercialOtherPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_CommercialAdvancestoMortgageBrokersSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_AgriculturalPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_AgriculturalRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_AgriculturalOtherPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_CommercialAndAgriculturalPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_ExcellentRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_HighQualityRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_HighSatisfactoryRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_LowSatisfactoryRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_VulnerableRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=isba_LossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |