SECURITIES (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 833,307	$ 789,229
Available-for-sale, Unrealized Gains	3,028	3,174
Available-for-sale, Unrealized Losses	(13,094)	(12,536)
Available-for-sale securities, at fair value	823,241	779,867
Held-to-maturity securities, at amortized cost	94,474	94,609
Held-to-maturity securities, Unrealized Gains	583	618
Held-to-maturity securities, Unrealized Losses	(713)	(631)
Held-to-maturity Securities, Fair Value	94,344	94,596
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	8,156	8,848
Available-for-sale, Unrealized Gains	130	153
Available-for-sale, Unrealized Losses	0	0
Available-for-sale securities, at fair value	8,286	9,001
Held-to-maturity securities, at amortized cost	94,474	94,609
Held-to-maturity securities, Unrealized Gains	583	618
Held-to-maturity securities, Unrealized Losses	(713)	(631)
Held-to-maturity Securities, Fair Value	94,344	94,596
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	526,135	485,222
Available-for-sale, Unrealized Gains	2,392	2,515
Available-for-sale, Unrealized Losses	(7,030)	(7,115)
Available-for-sale securities, at fair value	521,497	480,622
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	292,901	289,046
Available-for-sale, Unrealized Gains	172	265
Available-for-sale, Unrealized Losses	(6,064)	(5,421)
Available-for-sale securities, at fair value	287,009	283,890
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	5,483	5,481
Available-for-sale, Unrealized Gains	190	132
Available-for-sale, Unrealized Losses	0	0
Available-for-sale securities, at fair value	5,673	5,613
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	832,675	788,597
Available-for-sale, Unrealized Gains	2,884	3,065
Available-for-sale, Unrealized Losses	(13,094)	(12,536)
Available-for-sale securities, at fair value	822,465	779,126
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	632	632
Available-for-sale, Unrealized Gains	144	109
Available-for-sale, Unrealized Losses	0	0
Available-for-sale securities, at fair value	$ 776	$ 741

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
-SubTopic 10
-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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