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Qualified Affordable Housing (Details) - USD ($) | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2021 | Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019 | Sep. 11, 2019
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |
Investment in qualified affordable housing projects |  | $ 8,900,000 |  | $ 8,900,000 |  | $ 4,800,000 |
Tax credits to offset amortization expense of investments in affordable housing projects |  | 600,000 | $ 700,000 | 1,700,000 | $ 2,200,000 |  |
New Qualified Affordable Housing Project |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |
Investment in qualified affordable housing projects |  | 7,100,000 |  | 7,100,000 |  |  |
New qualified affordable housing project commitment |  |  |  |  |  |  | $ 10,200,000
Forecast | New Qualified Affordable Housing Project |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |
Amortization expense of investments in qualified affordable housing projects | $ 0 |  |  |  |  |  |
Tax credits to offset amortization expense of investments in affordable housing projects | $ 0 |  |  |  |  |  |
Noninterest Expense |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |
Amortization expense of investments in qualified affordable housing projects |  | $ 500,000 | $ 700,000 | $ 2,800,000 | $ 2,000,000.0 |  |

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- Definition Amount of affordable housing tax credits and other tax benefits recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 740 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985 + Details
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- Definition Amount of investment in qualified affordable housing projects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 740 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985 + Details
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- Definition Amount of amortization expense of investment in qualified affordable housing projects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 740 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985 + Details
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- Definition Amount of commitment or contingent commitments to qualified affordable housing project investments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 740 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985 + Details
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