DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	$ 936,958	$ 913,324
Estimate Fair Value Gain	12,445	13,477
Estimate Fair Value Loss	(13,427)	(14,431)
Fair Value Hedges | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	673,300	561,600
Fair Value Hedges | Pay fixed interest rate swaps with counterparty | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	9,632	9,836
Estimate Fair Value Gain	0	0
Estimate Fair Value Loss	(762)	(865)
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	463,663	451,744
Estimate Fair Value Gain	1,271	1,767
Estimate Fair Value Loss	(11,394)	(11,799)
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	463,663	451,744
Estimate Fair Value Gain	11,174	11,710
Estimate Fair Value Loss	$ (1,271)	$ (1,767)