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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Affordable Housing Entities (Narrative) (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Affordable Housing Projects [Abstract] |  |
Affordable housing projects, recognized amortization | $ 1,900,000 | $ 922,000
Affordable housing projects, tax credits | 2,900,000 | 1,100,000
Affordable housing projects, investment amount | 29,600,000 | 10,800,000
Affordable housing projects, liability | $ 12,000,000.0 | $ 9,900,000

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- Definition Affordable Housing Projects [Abstract] + References No definition available. + Details
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- Definition Amount of obligation related to Affordable Housing Program (AHP) assessments required by the Federal Home Loan Bank Act of 1932. + References No definition available. + Details
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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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