SECURITIES (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 719,807	$ 763,553
Available-for-sale, Unrealized Gains	8,528	7,434
Available-for-sale, Unrealized Losses	(4,098)	(7,924)
Available-for-sale, Fair Value	724,237	763,063
Held-to-maturity securities, at amortized cost	75,368	20,179
Held-to-maturity securities, Unrealized Gains	1,311	265
Held-to-maturity securities, Unrealized Losses	(101)	(19)
Held-to-maturity Securities, Fair Value	76,578	20,425
Obligations of U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	4,969	4,962
Available-for-sale, Unrealized Gains	125	65
Available-for-sale, Unrealized Losses	0	0
Available-for-sale, Fair Value	5,094	5,027
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	19,471	26,080
Available-for-sale, Unrealized Gains	401	697
Available-for-sale, Unrealized Losses	0	0
Available-for-sale, Fair Value	19,872	26,777
Held-to-maturity securities, at amortized cost	75,368	20,179
Held-to-maturity securities, Unrealized Gains	1,311	265
Held-to-maturity securities, Unrealized Losses	(101)	(19)
Held-to-maturity Securities, Fair Value	76,578	20,425
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	376,950	377,657
Available-for-sale, Unrealized Gains	5,490	5,656
Available-for-sale, Unrealized Losses	(1,391)	(2,005)
Available-for-sale, Fair Value	381,049	381,308
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	318,417	348,855
Available-for-sale, Unrealized Gains	2,512	953
Available-for-sale, Unrealized Losses	(2,707)	(5,911)
Available-for-sale, Fair Value	$ 318,222	343,897
Private issue collateralized mortgage obligations
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost		5,999
Available-for-sale, Unrealized Gains		63
Available-for-sale, Unrealized Losses		(8)
Available-for-sale, Fair Value		$ 6,054

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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