FAIR VALUE - Summary of assets and liabilities measured at fair value on a recurring or nonrecurring, the significant unobservable inputs (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Estimate	$ 194	$ 658
Commercial and Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Estimate	$ 1,800	$ 3,579
Discount | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount		0.50%
Discount | Level 3 | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount	5.00%
Discount rate | Level 3 | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset	3
Maximum | Commission and Cost to Sell | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of commission and cost to sell		0.10%
Maximum | Discount rate | Commercial and Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount rate	0.35%	50.00%
Minimum | Commission and Cost to Sell | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of commission and cost to sell		0.01%
Minimum | Discount rate | Commercial and Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount rate	0.17%	0.00%
Weighted Average | Commission and Cost to Sell | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of commission and cost to sell	0.05%	0.07%
Weighted Average | Discount rate | Commercial properties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount rate		0.50%
Weighted Average | Discount rate | Commercial and Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range and weighted average of discount rate	0.26%	23.00%
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset, Fair Value	$ 232
Guarantee liability	(125)
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset, Fair Value	232
Guarantee liability	$ (125)
Recurring | Discount rate | Level 3 | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee liability	3
Recurring | Prepayment rate | Level 3 | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset, Fair Value	$ 232
Guarantee liability	$ (125)
Guarantee asset	25
Guarantee liability	25
Recurring | Pull through | Level 3 | Best execution model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net, Fair Value	$ 9,752	$ 1,184
Recurring | Maximum | Pull through | Level 3 | Best execution model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net	100	100
Recurring | Minimum | Pull through | Level 3 | Best execution model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net	55	75
Recurring | Weighted Average | Discount rate | Level 3 | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset	3
Guarantee liability	3
Recurring | Weighted Average | Prepayment rate | Level 3 | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guarantee asset	25
Guarantee liability	25
Recurring | Weighted Average | Pull through | Level 3 | Best execution model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net	86	88
Recurring | IRLC and FSC, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net, Fair Value	$ 9,752	$ 1,184
Recurring | IRLC and FSC, net | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
IRLC and FSC, net, Fair Value	$ 9,752	$ 1,184