FAIR VALUE MEASUREMENTS - Unobservable Inputs Used and Valuation Techniques (Details) - Level 3	Mar. 31, 2022
Mortgage servicing rights | Minimum | Discounted Cash Flow | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0774
Mortgage servicing rights | Minimum | Discounted Cash Flow | Option adjusted spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	4
Mortgage servicing rights | Maximum | Discounted Cash Flow | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.2235
Mortgage servicing rights | Maximum | Discounted Cash Flow | Option adjusted spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	10.60
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	0.088
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	6.21
Customer commodity contracts | Minimum | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.1862
Customer commodity contracts | Minimum | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.0437
Customer commodity contracts | Maximum | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	1.0006
Customer commodity contracts | Maximum | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	1.7745
Customer commodity contracts | Weighted Average | Internal Model | Pull through rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	0.8266
Customer commodity contracts | Weighted Average | Internal Model | MSR value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other derivative contracts, measurement input	1.0000