SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2019 USD ($) subsidary Family Residentialhouse segment	Mar. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Number of subsidiaries | subsidary		6
Number of families secured by loans of real estate | Family		4
Goodwill impairment		$ 0
Number of operating segments | segment		1
Number of reportable operating segments | segment		1
Operating lease right of use asset		$ 11,554,000
Operating lease liability		$ 11,675,000
Accounting Standards Update 2016-02
Property, Plant and Equipment [Line Items]
Operating lease right of use asset			$ 12,000,000.0
Operating lease liability			12,000,000.0
Accumulated Other Comprehensive Loss | Accounting Standards Update 2018-02
Property, Plant and Equipment [Line Items]
Reclassification of certain tax effects from accumulated other comprehensive income			486,000
Retained Earnings | Accounting Standards Update 2018-02
Property, Plant and Equipment [Line Items]
Reclassification of certain tax effects from accumulated other comprehensive income			$ 486,000
Core Deposits
Property, Plant and Equipment [Line Items]
Core deposit amortization period		10 years
Maximum
Property, Plant and Equipment [Line Items]
Number of housing units secured by loans from segment | Residentialhouse		5
Maximum | Accounting Standards Update 2016-13 | Subsequent Event
Property, Plant and Equipment [Line Items]
Increase to allowance for credit losses, percent	30.00%
Minimum | Accounting Standards Update 2016-13 | Subsequent Event
Property, Plant and Equipment [Line Items]
Increase to allowance for credit losses, percent	20.00%