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FAIR VALUE MEASUREMENTS - Information about Significant Unobservable Inputs Used for Recurring Fair Value Measurements for Level 3 MSRs (Detail) - Fair Value, Measurements, Recurring - Level 3 - Mortgage Servicing Rights | 3 Months Ended | 12 Months Ended
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Mar. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Unobservable input, cost to service | $ 81 | $ 83
Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Unobservable input, cost to service | 107 | 108
Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Unobservable input, cost to service | $ 97 | $ 98
Discount rate | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.090 | 0.090
Discount rate | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.120 | 0.120
Discount rate | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.090 | 0.094
Prepayment rate | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.110 | 0.193
Prepayment rate | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.392 | 0.555
Prepayment rate | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.269 | 0.420
Delinquency rate | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.000 | 0.000
Delinquency rate | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.060 | 0.060
Delinquency rate | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
MSR measurement inputs | 0.025 | 0.025

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- 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
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- Definition Value of input used to measure servicing asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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