SECURITIES (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 778,735	$ 756,186
Available-for-sale, Unrealized Gains	11,201	4,293
Available-for-sale, Unrealized Losses	(1,056)	(10,141)
Available-for-sale, Fair Value	788,880	750,338
Held-to-maturity securities, at amortized cost	94,205	84,144
Held-to-maturity securities, Unrealized Gains	3,898	1,564
Held-to-maturity securities, Unrealized Losses	(7)	(61)
Held-to-maturity Securities, Fair Value	98,096	85,647
Obligations of U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	15,721	4,971
Available-for-sale, Unrealized Gains	134	69
Available-for-sale, Unrealized Losses	0	0
Available-for-sale, Fair Value	15,855	5,040
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	9,763	17,355
Available-for-sale, Unrealized Gains	238	339
Available-for-sale, Unrealized Losses	0	0
Available-for-sale, Fair Value	10,001	17,694
Held-to-maturity securities, at amortized cost	94,205	84,144
Held-to-maturity securities, Unrealized Gains	3,898	1,564
Held-to-maturity securities, Unrealized Losses	(7)	(61)
Held-to-maturity Securities, Fair Value	98,096	85,647
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	442,099	419,429
Available-for-sale, Unrealized Gains	8,366	3,474
Available-for-sale, Unrealized Losses	(157)	(3,857)
Available-for-sale, Fair Value	450,308	419,046
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	305,039	312,719
Available-for-sale, Unrealized Gains	2,222	409
Available-for-sale, Unrealized Losses	(899)	(6,271)
Available-for-sale, Fair Value	306,362	306,857
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	5,481	1,000
Available-for-sale, Unrealized Gains	223	0
Available-for-sale, Unrealized Losses	0	(4)
Available-for-sale, Fair Value	5,704	996
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	778,103	755,474
Available-for-sale, Unrealized Gains	11,183	4,291
Available-for-sale, Unrealized Losses	(1,056)	(10,132)
Available-for-sale, Fair Value	788,230	749,633
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	632	712
Available-for-sale, Unrealized Gains	18	2
Available-for-sale, Unrealized Losses	0	(9)
Available-for-sale, Fair Value	$ 650	$ 705

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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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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