MORTGAGE BANKING ACTIVITIES - OTHER INFORMATION RELATING TO MSRS (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Mortgage Servicing Rights    
Fair value of mortgage servicing rights portfolio $ 7,478 $ 7,242
Discount rate (as percent) 13.00% 10.00%
Weighted average default rate (as percent) 1.50% 1.50%
Weighted average life in years 6 years 9 months 6 years 4 months 17 days
Minimum    
Mortgage Servicing Rights    
Monthly prepayment rate of unpaid principle balance (as percent) 104.00% 105.00%
Maximum    
Mortgage Servicing Rights    
Monthly prepayment rate of unpaid principle balance (as percent) 419.00% 369.00%