SECURITIES (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 788,153	$ 761,138
Available-for-sale, Unrealized Gains	18,084	20,808
Available-for-sale, Unrealized Losses	(2,617)	(896)
Available-for-sale, Fair Value	803,620	781,050
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	29,181	31,112
Available-for-sale, Unrealized Gains	1,786	1,928
Available-for-sale, Unrealized Losses
Available-for-sale, Fair Value	30,967	33,040
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	340,550	345,528
Available-for-sale, Unrealized Gains	10,925	12,699
Available-for-sale, Unrealized Losses	(630)	(79)
Available-for-sale, Fair Value	350,845	358,148
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	409,866	375,627
Available-for-sale, Unrealized Gains	5,373	6,181
Available-for-sale, Unrealized Losses	(1,325)	(120)
Available-for-sale, Fair Value	413,914	381,688
Private issue collateralized mortgage obligations
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	8,556	8,871
Available-for-sale, Unrealized Gains
Available-for-sale, Unrealized Losses	(662)	(697)
Available-for-sale, Fair Value	$ 7,894	$ 8,174

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details