MORTGAGE BANKING - Economic Assumptions Used to Estimate Value of MSRs Capitalized (Details) - Residential mortgages	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Servicing Assets at Fair Value [Line Items]
Weighted average life (in years)	6 years 10 months 24 days	6 years 1 month 6 days
Weighted average constant prepayment rate	8.70%	11.00%
Weighted average discount rate	9.90%	9.80%