XML 50 R39.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Investment Securities - Fair value of securities held-to-maturity and available-for-sale (Details) - USD ($) $ in Thousands | Sep. 30, 2022 | Dec. 31, 2021
--- | --- | ---
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months | $ 8,156 | $ 94,506
Fair Value, 12 Months or Longer | 73,609 | 8,751
Fair Value | 81,765 | 103,257
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (1,620) | (2,035)
Gross Unrealized Losses, 12 Months or Longer | (17,213) | (216)
Gross Unrealized Losses | (18,833) | (2,251)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 252,199 | 168,443
Fair Value, 12 Months or Longer | 114,347 | 7,795
Fair Value | 366,546 | 176,238
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (19,825) | (2,723)
Gross Unrealized Losses, 12 Months or Longer | (19,655) | (269)
Gross Unrealized Losses | (39,480) | (2,992)
U.S Treasuries |  |
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months |  | 5,851
Fair Value, 12 Months or Longer | 5,105 |
Fair Value | 5,105 | 5,851
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months |  | (150)
Gross Unrealized Losses, 12 Months or Longer | (895) |
Gross Unrealized Losses | (895) | (150)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 39,019 | 30,543
Fair Value, 12 Months or Longer | 19,800 |
Fair Value | 58,819 | 30,543
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (2,025) | (411)
Gross Unrealized Losses, 12 Months or Longer | (2,560) |
Gross Unrealized Losses | (4,585) | (411)
U.S. government and federal agencies |  |
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months | 834 | 31,617
Fair Value, 12 Months or Longer | 28,436 | 3,376
Fair Value | 29,270 | 34,993
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (166) | (645)
Gross Unrealized Losses, 12 Months or Longer | (6,152) | (81)
Gross Unrealized Losses | (6,318) | (726)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 20,293 | 14,154
Fair Value, 12 Months or Longer | 14,163 | 6,877
Fair Value | 34,456 | 21,031
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (1,831) | (301)
Gross Unrealized Losses, 12 Months or Longer | (2,430) | (223)
Gross Unrealized Losses | (4,261) | (524)
Collateralized mortgage obligations |  |
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months | 5,679 | 25,072
Fair Value, 12 Months or Longer | 12,090 |
Fair Value | 17,769 | 25,072
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (1,126) | (534)
Gross Unrealized Losses, 12 Months or Longer | (3,029) |
Gross Unrealized Losses | (4,155) | (534)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 20,001 | 30,352
Fair Value, 12 Months or Longer | 20,210 |
Fair Value | 40,211 | 30,352
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (1,507) | (726)
Gross Unrealized Losses, 12 Months or Longer | (4,470) |
Gross Unrealized Losses | (5,977) | (726)
Taxable municipal |  |
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months |  | 3,971
Fair Value, 12 Months or Longer | 4,736 | 1,923
Fair Value | 4,736 | 5,894
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months |  | (133)
Gross Unrealized Losses, 12 Months or Longer | (1,340) | (61)
Gross Unrealized Losses | (1,340) | (194)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 336 | 265
Fair Value, 12 Months or Longer | 242 |
Fair Value | 578 | 265
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (2) | (5)
Gross Unrealized Losses, 12 Months or Longer | (28) |
Gross Unrealized Losses | (30) | (5)
Mortgage-backed |  |
Held-to-maturity, Fair Value |  |
Fair Value, Less than 12 Months | 1,643 | 27,995
Fair Value, 12 Months or Longer | 23,242 | 3,452
Fair Value | 24,885 | 31,447
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (328) | (573)
Gross Unrealized Losses, 12 Months or Longer | (5,797) | (74)
Gross Unrealized Losses | (6,125) | (647)
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 165,485 | 93,129
Fair Value, 12 Months or Longer | 59,932 | 918
Fair Value | 225,417 | 94,047
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (13,529) | (1,280)
Gross Unrealized Losses, 12 Months or Longer | (10,167) | (46)
Gross Unrealized Losses | (23,696) | $ (1,326)
Corporate bonds |  |
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 2,692 |
Fair Value | 2,692 |
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (308) |
Gross Unrealized Losses | (308) |
Tax-exempt municipal |  |
Available-for-sale, Fair Value |  |
Fair Value, Less than 12 Months | 4,373 |
Fair Value | 4,373 |
Gross Unrealized Losses |  |
Gross Unrealized Losses, Less than 12 Months | (623) |
Gross Unrealized Losses | $ (623) |

X
- References No definition available. + Details
Name: | jmsb_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionFairValueAbstract
Namespace Prefix: | jmsb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValueAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CollateralizedMortgageObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_TaxableMunicipalNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_NontaxableMunicipalNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |