FAIR VALUE - Summary of assets measured at fair value on recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	$ 36,666	$ 58,903
U.S. Treasury debt
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	254	254
Corporate bonds
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	6,044
Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	36,666	58,903
Equity securities	730	713
Guarantee asset	232
Guarantee liability	(125)
Recurring | U.S. Treasury debt
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	254	254
Recurring | Corporate bonds
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	6,044
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	4,087	10,420
Recurring | IRLC and FSC, net
Summary of assets measured on a recurring and nonrecurring basis
Derivative asset, Fair value	9,752	1,184
Recurring | GNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	24,604	45,312
Recurring | FNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	1,677	2,917
Level 1 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	254	254
Equity securities	730	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	254	254
Level 2 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	36,412	58,649
Level 2 | Recurring | Corporate bonds
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	6,044
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	4,087	10,420
Level 2 | Recurring | GNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	24,604	45,312
Level 2 | Recurring | FNMA
Summary of assets measured on a recurring and nonrecurring basis
Available-for-sale securities, at fair value	1,677	2,917
Level 3 | Recurring
Summary of assets measured on a recurring and nonrecurring basis
Guarantee asset	232
Guarantee liability	(125)
Level 3 | Recurring | IRLC and FSC, net
Summary of assets measured on a recurring and nonrecurring basis
Derivative asset, Fair value	$ 9,752	$ 1,184