MORTGAGE BANKING - Economic Assumptions Used to Estimate Value of MSRs Capitalized (Details) - Residential mortgages	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Servicing Assets at Fair Value [Line Items]
Weighted average life (in years)	6 years 2 months 12 days	5 years 10 months 24 days	6 years 7 months 6 days	6 years
Weighted average constant prepayment rate	11.10%	11.30%	9.90%	11.10%
Weighted average discount rate	9.90%	9.70%	9.90%	9.70%