FAIR VALUE MEASUREMENTS - Unobservable Inputs Used and Valuation Techniques (Details) - Level 3	Dec. 31, 2021
Mortgage servicing rights | Minimum | Discounted Cash Flow | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0940
Mortgage servicing rights | Minimum | Discounted Cash Flow | Option adjusted spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	3.70
Mortgage servicing rights | Maximum | Discounted Cash Flow | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.2632
Mortgage servicing rights | Maximum | Discounted Cash Flow | Option adjusted spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	12.28
Mortgage servicing rights | Weighted Average | Discounted Cash Flow | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.1070
Mortgage servicing rights | Weighted Average | Discounted Cash Flow | Option adjusted spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	5.96
Other derivative contracts | Minimum | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.0939
Other derivative contracts | Minimum | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	(0.1700)
Other derivative contracts | Maximum | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	1.0000
Other derivative contracts | Maximum | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	1.6875
Other derivative contracts | Weighted Average | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.7751
Other derivative contracts | Weighted Average | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.9613