XML 40 R30.htm IDEA: XBRL DOCUMENT
v3.25.3

LOANS RECEIVABLE - Allowance for Credit Losses (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | $ 2,522 |  |
Charge-offs | (153) |  | $ (392)
Ending Balance | 2,397 |  | 2,522
Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 2,522 | $ 2,124 | 2,124
Provision (Reversal) | (42) | 557 |
Charge-offs | (153) | (364) |
Recoveries | 70 | 97 |
Ending Balance | 2,397 | 2,414 | 2,522
Loans and finance receivables |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 2,643 | 2,381 | 2,381
Provision (Reversal) | (36) | 531 |
Charge-offs | (153) | (364) |
Recoveries | 70 | 97 |
Ending Balance | 2,524 | 2,645 | 2,643
Unfunded Lending Commitments | Financing Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 121 | 257 | 257
Provision (Reversal) | 6 | (26) |
Ending Balance | 127 | 231 | 121
One- to four-family residential |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 1,164 |  |
Charge-offs | (113) |  | (182)
Ending Balance | 1,166 |  | 1,164
One- to four-family residential | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 1,164 | 1,240 | 1,240
Provision (Reversal) | 81 | 62 |
Charge-offs | (113) | (160) |
Recoveries | 34 | 68 |
Ending Balance | 1,166 | 1,210 | 1,164
Commercial real estate |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 192 |  |
Charge-offs |  |  | (28)
Ending Balance | 302 |  | 192
Commercial real estate | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 192 | 213 | 213
Provision (Reversal) | 110 | 17 |
Charge-offs |  | (28) |
Recoveries |  | 14 |
Ending Balance | 302 | 216 | 192
Construction and land |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 528 |  |
Ending Balance | 282 |  | 528
Construction and land | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 528 | 283 | 283
Provision (Reversal) | (246) | 258 |
Ending Balance | 282 | 541 | 528
Multi-family residential |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 35 |  |
Ending Balance | 72 |  | 35
Multi-family residential | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 35 | 50 | 50
Provision (Reversal) | 37 | (13) |
Ending Balance | 72 | 37 | 35
Commercial and industrial |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 372 |  |
Charge-offs |  |  | (133)
Ending Balance | 332 |  | 372
Commercial and industrial | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 372 | 302 | 302
Provision (Reversal) | (57) | 206 |
Charge-offs |  | (133) |
Recoveries | 17 | 4 |
Ending Balance | 332 | 379 | 372
Consumer |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 26 |  |
Charge-offs | (40) |  | (49)
Ending Balance | 38 |  | 26
Consumer | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 26 | 36 | 36
Provision (Reversal) | 33 | 27 |
Charge-offs | (40) | (43) |
Recoveries | 19 | 11 |
Ending Balance | 38 | $ 31 | 26
Unallocated |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 205 |  |
Ending Balance | 205 |  | 205
Unallocated | Loans Receivable |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] |  |  |
Beginning Balance | 205 |  |
Ending Balance | $ 205 |  | $ 205

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-22 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_LoansReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_LoansAndFinanceReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_FinanceReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=clst_OneToFourFamilyResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=clst_ConstructionAndLandPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=clst_MultiFamilyResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |