FAIR VALUE MEASUREMENTS - Unobservable Inputs Non-recurring (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Other real estate owned	$ 2,455,000	$ 2,351,000
Non-recurring \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Impaired loans	14,382,000	15,213,000
Capitalized servicing rights	4,108,000	4,882,000
Other real estate owned	2,455,000	2,351,000
Total	22,846,000	22,446,000
Carrying value of assets held for sale	1,800,000	0
Non-recurring \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Impaired loans	11,419,000	11,676,000
Other real estate owned	2,455,000	2,351,000
Non-recurring \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Impaired loans	2,963,000	3,537,000
Capitalized servicing rights	4,108,000	4,882,000
Non-recurring \| Valuation, market approach \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value	136,000
Carrying value of assets held for sale	1,901,000
Non-recurring \| Minimum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value	0
Non-recurring \| Maximum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value	6,915,000
Non-recurring \| Maximum \| Valuation, market approach \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value	527,000
Non-recurring \| Impaired loans \| Minimum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value		0
Non-recurring \| Impaired loans \| Minimum \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Cash flows	22,000	22,000
Non-recurring \| Impaired loans \| Maximum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value		6,915,000
Non-recurring \| Impaired loans \| Maximum \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Cash flows	1,019,000	1,072,000
Non-recurring \| Other real estate owned \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Appraised value	$ 2,695,000	$ 2,700,000
Selling Costs		12.93%
Non-recurring \| Other real estate owned \| Minimum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Selling Costs	6.00%
Non-recurring \| Other real estate owned \| Maximum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Selling Costs	10.00%
Loss severity \| Non-recurring \| Impaired loans \| Minimum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Loss severity	0.00%	0.00%
Loss severity \| Non-recurring \| Impaired loans \| Maximum \| Fair value of collateral -appraised value \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Loss severity	61.00%	55.00%
Constant prepayment rate (CPR) \| Non-recurring \| Capitalized servicing rights \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Constant prepayment rate (CPR)	10.21%	8.19%
Discount rate \| Non-recurring \| Impaired loans \| Minimum \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Discount rate	2.88%	2.88%
Discount rate \| Non-recurring \| Impaired loans \| Maximum \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Discount rate	9.50%	9.50%
Discount rate \| Non-recurring \| Capitalized servicing rights \| Discount cash flow \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items}
Discount rate	10.08%	10.08%

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- Definition

Fair Value Inputs, Cash Flow

+ References

No definition available.

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- Definition

Fair Value Inputs, Selling Costs

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No definition available.

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- Definition

Represents the amount of impaired loans assets reported on the balance sheet at period end measured at fair value by the entity.

+ References

No definition available.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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- Definition

Fair value portion of assets classified as held for sale.

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Reference 1: http://www.xbrl.org/2003/role/exampleRef
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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.

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No definition available.

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- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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- Definition

Discount rate used to estimate the fair value of servicing assets and servicing liabilities.

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- Definition

Percentage of contractually collectible principal associated with a financial asset expected not to be collected due to default by the borrower.

+ References

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- Definition

Estimated rate of prepayments of principal on servicing assets and servicing liabilities.

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