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MORTGAGE BANKING OPERATIONS - Key Economic Assumptions (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques
Servicing asset, measurement input	9.84%		8.75%
Constant prepayment rate | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Servicing asset, measurement input		20.00%		17.10%
Constant prepayment rate | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Servicing asset, measurement input		30.00%		30.00%
Discount rate
Fair Value Measurement Inputs and Valuation Techniques
Servicing asset, measurement input	7.77%	7.71%	8.25%	7.78%

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