BORROWINGS - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
Aug. 02, 2019	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Residential real estate loans and securities pledged as collateral for FHLB advances, carrying value		$ 453.2	$ 412.9
FHLB Stock owned		10.4	10.4
FHLB borrowing capacity, authorized		800.0
Line of Credit Facility, Current Borrowing Capacity		115.5
Commercial loans pledged as collateral for Federal Reserve Discount Window, carrying value		446.9	381.5
Federal Reserve borrowing capacity		339.5	286.5
Secured Debt		170.0
Line of Credit Facility, Remaining Borrowing Capacity		325.0
Unsecured revolving credit agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 30.0
Term of credit agreement	1 year
Amount drawn on the line		0.0
American Financial Exchange
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		$ 244.0	$ 119.0

The amount authorized to borrow from the Federal Home Loan Bank.

No definition available.

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- Definition

The amount authorized to borrow from the Federal Reserve Bank.

+ References

No definition available.

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- Definition

The carrying amount as of the date of the latest financial statement presented of commercial loans which are owned but transferred to the Federal Reserve to serve as collateral to partially or fully secure a debt obligation and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

No definition available.

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- Definition

The carrying amount as of the date of the latest financial statement presented of residential mortgage loans and mortgage-related securities classified as available for sale which are owned but transferred to the FHLB to serve as collateral to partially or fully secure a debt obligation and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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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.

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

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-Section S99
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
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