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Business Combination and Asset Purchase - Summary of Changes in Accretable Yield or Income Expected to be Collected (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
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Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022
Peoples Federal Savings and Loan [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Beginning Balance | $ 680 |  | $ 798 |  |
Additions | 2 |  | 6 |  |
Accretion | (58) |  | (174) |  |
Disposals |  |  | (6) |  |
Ending Balance | 624 |  | 624 |  | $ 798
Perpetual Federal Savings Bank [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Beginning Balance | 3,572 | $ 4,710 | 4,236 | $ 5,262 | 5,262
Additions | 14 | 28 | 39 | 125 |
Accretion | (456) | (330) | (1,145) | (979) |
Disposals |  | (2) |  | (2) |
Ending Balance | 3,130 | 4,406 | 3,130 | 4,406 | 4,236
Ossian Financial Services, Inc. [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Beginning Balance | 382 | 557 | 470 | 645 | 645
Additions |  | 1 |  | 1 |
Accretion | (44) | (44) | (132) | (132) |
Ending Balance | 338 | 514 | 338 | 514 | 470
Limberlost Bancshares, Inc. [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Beginning Balance | 575 | 994 | 785 | 1,198 | 1,198
Additions | 6 | 2 | 11 | 10 |
Accretion | (109) | (107) | (324) | (319) |
Ending Balance | $ 472 | $ 889 | $ 472 | $ 889 | $ 785

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- Definition The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481906/310-30-15-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481696/310-30-50-2 + Details
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- Definition Current period recognition due to accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481906/310-30-15-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481696/310-30-50-2 + Details
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- Definition Increases in the aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan due to the acquisition of similar loans accounted for as debt securities during the period. This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481906/310-30-15-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481696/310-30-50-2 + Details
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- Definition Sale or transfer of a loan during the period resulting in a reduction in the excess of a loan's cash flows expected to be collected over the investor's initial investment. This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481906/310-30-15-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481696/310-30-50-2 + Details
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