XML 42 R30.htm IDEA: XBRL DOCUMENT
v3.21.2

Schedule of Available-for-sale Securities (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Investment Holdings [Line Items] |  |
Amortized cost | $ 370,688 | $ 284,758
Gross unrealized gains | 8,456 | 12,542
Gross unrealized losses | (626) | (30)
Estimated fair value | 378,518 | 297,270
US Treasury Securities [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 40,397 | 2,000
Gross unrealized gains | 11 | 37
Gross unrealized losses | (94) |
Estimated fair value | 40,314 | 2,037
U.S. Federal Agency Obligations [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 17,211 | 18,804
Gross unrealized gains | 95 | 138
Gross unrealized losses | (9) | (18)
Estimated fair value | 17,297 | 18,924
Municipal Obligations, Tax Exempt [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 135,818 | 136,321
Gross unrealized gains | 4,999 | 6,367
Gross unrealized losses | (29) | (12)
Estimated fair value | 140,788 | 142,676
Municipal Obligations, Taxable [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 37,599 | 46,643
Gross unrealized gains | 1,447 | 2,892
Gross unrealized losses | (58) |
Estimated fair value | 38,988 | 49,535
Agency Mortgage-backed Securities [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 132,034 | 75,530
Gross unrealized gains | 1,904 | 3,108
Gross unrealized losses | (436) |
Estimated fair value | 133,502 | 78,638
Certificates of Deposit [Member] |  |
Investment Holdings [Line Items] |  |
Amortized cost | 7,629 | 5,460
Gross unrealized gains |  |
Gross unrealized losses |  |
Estimated fair value | $ 7,629 | $ 5,460

X
- Definition Available for sale of securities. + References No definition available. + Details
Name: | LARK_AvailableForSaleOfSecurities
Namespace Prefix: | LARK_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Available for sale of securities accumulated gross unrealized loss before tax. + References No definition available. + Details
Name: | LARK_AvailableForSaleOfSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | LARK_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Available for sale of securities amortized cost. + References No definition available. + Details
Name: | LARK_AvailableForSaleOfSecuritiesAmortizedCost
Namespace Prefix: | LARK_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Available for sale of securities accumulated gross unrealized gain before tax. + References No definition available. + Details
Name: | LARK_AvailableForSaleoFSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | LARK_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_InvestmentHoldingsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=LARK_USFederalAgencyObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=LARK_MunicipalObligationsTaxExemptMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=LARK_MunicipalObligationsTaxableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=LARK_AgencyMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |