SHORT-TERM BORROWINGS - Contractual Maturity of Repurchase Agreements (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Remaining Contractual Maturity of the Agreements      
Short-term borrowings $ 13,241 $ 46,638  
Repurchase Agreements      
Remaining Contractual Maturity of the Agreements      
Short-term borrowings 13,241 18,334 $ 13,987
Overnight and Continuous      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement 20,900 24,084  
Overnight and Continuous | U.S. Government and agency securities      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement 0 3,586  
Overnight and Continuous | Mortgage-back securities      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement 6,684 8,368  
Overnight and Continuous | Asset-backed securities      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement 109 1,960  
Overnight and Continuous | State and political securities      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement 5,241 8,015  
Overnight and Continuous | Other debt securities      
Remaining Contractual Maturity of the Agreements      
Securities borrowed, gross including not subject to master netting arrangement $ 8,866 $ 2,155