FAIR VALUE MEASUREMENT (Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financial Assets:
Securities available-for-sale	$ 772,467	$ 808,477
Trading account assets	2,406	2,488
Customer interest rate swap agreements	584	114
Financial Liabilities:
Interest rate swap agreements	6,826	3,911
Customer interest rate swap agreements	584	114
US Government-sponsored Enterprises Debt Securities
Financial Assets:
Securities available-for-sale	5,016
Obligations of states and political subdivisions
Financial Assets:
Securities available-for-sale	28,129	31,207
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	377,173	395,903
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	355,591	374,435
Private issue collateralized mortgage obligations
Financial Assets:
Securities available-for-sale	6,558	6,932
Fair Value, Measurements, Recurring
Financial Assets:
Trading account assets	2,406	2,488
Customer interest rate swap agreements	584	114
Financial Liabilities:
Interest rate swap agreements	6,826	3,911
Customer interest rate swap agreements	584	114
Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Financial Assets:
Securities available-for-sale	5,016
Fair Value, Measurements, Recurring | Obligations of states and political subdivisions
Financial Assets:
Securities available-for-sale	28,129	31,207
Fair Value, Measurements, Recurring | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	377,173	395,903
Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	355,591	374,435
Fair Value, Measurements, Recurring | Private issue collateralized mortgage obligations
Financial Assets:
Securities available-for-sale	6,558	6,932
Readily Available Market Prices (Level 1)
Financial Assets:
Securities available-for-sale	0	0
Trading account assets	2,406	2,488
Customer interest rate swap agreements	0	0
Financial Liabilities:
Interest rate swap agreements	0	0
Customer interest rate swap agreements	0	0
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring
Financial Assets:
Trading account assets		2,488
Customer interest rate swap agreements
Financial Liabilities:
Interest rate swap agreements
Customer interest rate swap agreements	0	0
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Financial Assets:
Securities available-for-sale
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring | Obligations of states and political subdivisions
Financial Assets:
Securities available-for-sale
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale
Readily Available Market Prices (Level 1) | Fair Value, Measurements, Recurring | Private issue collateralized mortgage obligations
Financial Assets:
Securities available-for-sale
Trading account assets	2,406
Observable Market Data (Level 2)
Financial Assets:
Securities available-for-sale	772,467	808,477
Trading account assets	0	0
Customer interest rate swap agreements	584	114
Financial Liabilities:
Interest rate swap agreements	6,826	3,911
Customer interest rate swap agreements	584	114
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring
Financial Assets:
Trading account assets
Customer interest rate swap agreements	584	114
Financial Liabilities:
Interest rate swap agreements	6,826	3,911
Customer interest rate swap agreements	584	114
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Financial Assets:
Securities available-for-sale	5,016
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring | Obligations of states and political subdivisions
Financial Assets:
Securities available-for-sale	28,129	31,207
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	377,173	395,903
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale	355,591	374,435
Observable Market Data (Level 2) | Fair Value, Measurements, Recurring | Private issue collateralized mortgage obligations
Financial Assets:
Securities available-for-sale	6,558	6,932
Company Determined Fair Value (Level 3)
Financial Assets:
Securities available-for-sale	0	0
Trading account assets	0	0
Customer interest rate swap agreements	0	0
Financial Liabilities:
Interest rate swap agreements	0	0
Customer interest rate swap agreements	0	0
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring
Financial Assets:
Trading account assets
Customer interest rate swap agreements
Financial Liabilities:
Interest rate swap agreements
Customer interest rate swap agreements	0	0
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Financial Assets:
Securities available-for-sale
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring | Obligations of states and political subdivisions
Financial Assets:
Securities available-for-sale
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Financial Assets:
Securities available-for-sale
Company Determined Fair Value (Level 3) | Fair Value, Measurements, Recurring | Private issue collateralized mortgage obligations
Financial Assets:
Securities available-for-sale