SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)			3 Months Ended		9 Months Ended
	Mar. 16, 2020	Jan. 01, 2020 USD ($)	Sep. 30, 2020 USD ($) subsidary Family Residentialhouse	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) subsidary Family Residentialhouse	Sep. 30, 2019 USD ($)	Mar. 27, 2020 USD ($)	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Number of subsidiaries | subsidary			6		6
Provision for loan losses			$ (300,000)	$ 100,000	$ 13,200,000	$ 1,250,000
Decrease to retained earnings			$ 105,721,000		105,721,000			$ 98,239,000
Retained earnings, net of tax					$ 955,000
Number of families secured by loans of real estate | Family			4		4
Number of housing units secured by loans from segment | Residentialhouse			5		5
Paycheck Protection Program Loans
Property, Plant and Equipment [Line Items]
Percentage of government guaranteed loans			100.00%		100.00%
ASU 2017-04
Property, Plant and Equipment [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]			true		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date			Jan. 01, 2020		Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]			true		true
Accounting Standards Update 2016-13
Property, Plant and Equipment [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]			true		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date			Jan. 01, 2020		Jan. 01, 2020
Increase to allowance for credit losses		$ 4,548,000
Increase to allowance for credit losses, percent		28.10%
Provision for loan losses			$ 13,200,000		$ 13,200,000
Accounting Standards Update 2016-13 | Cumulative Effect | Revision of Prior Period, Adjustment
Property, Plant and Equipment [Line Items]
Decrease to retained earnings			$ (3,593,000)		(3,593,000)
Retained earnings, net of tax					$ 955,000
COVID-19
Property, Plant and Equipment [Line Items]
Maximum authorized amount of coronavirus aid, relief and economic security							$ 2,000,000,000,000
Description of federal fund interest rate					Due to the COVID-19 pandemic, market interest rates have declined significantly, with the 10-year Treasury bond falling below 1.00% on March 3, 2020 for the first time. On March 16, 2020, the Federal Open Market Committee reduced the target federal funds rate range to 0.00% to 0.25%.
COVID-19 | Minimum
Property, Plant and Equipment [Line Items]
Federal open market committee reduced target federal funds interest rate.	0.00%
COVID-19 | Maximum
Property, Plant and Equipment [Line Items]
Federal open market committee reduced target federal funds interest rate.	0.25%