FAIR VALUE - Summary of assets measured at fair value on recurring basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	$ 47,018	$ 58,903
U.S. Treasury debt
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	257	254
Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	47,018	58,903
Equity securities	732	713
Guarantee asset	222
Guarantee liability	191
Recurring | U.S. Treasury debt
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	257	254
Recurring | Corporate collateralized mortgage obligations and mortgage-backed securities
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	7,556	10,420
Recurring | Interest rate lock and forward delivery commitments
Summary of assets measured on a recurring and nonrecurring basis
Derivative asset, Fair value	7,482	1,184
Recurring | GNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	36,469	45,312
Recurring | FNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	2,736	2,917
Level 1 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	257	254
Equity securities	732	713
Level 1 | Recurring | U.S. Treasury debt
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	257	254
Level 2 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	46,761	58,649
Level 2 | Recurring | Corporate collateralized mortgage obligations and mortgage-backed securities
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	7,556	10,420
Level 2 | Recurring | GNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	36,469	45,312
Level 2 | Recurring | FNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	2,736	2,917
Level 3 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Guarantee asset	222
Guarantee liability	191
Level 3 | Recurring | Interest rate lock and forward delivery commitments
Summary of assets measured on a recurring and nonrecurring basis
Derivative asset, Fair value	$ 7,482	$ 1,184