SECURITIES (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized Cost	$ 922,870	$ 891,276
Gross Unrealized Gains	20,083	16,661
Gross Unrealized (Losses)	(3,544)	(4,645)
Available for sale securities, Estimated fair value	939,409	903,292
Obligations of States and Political Subdivisions [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized Cost	254,851	257,740
Gross Unrealized Gains	11,267	10,479
Gross Unrealized (Losses)	(149)	(140)
Available for sale securities, Estimated fair value	265,969	268,079
Corporate and Other Bonds [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized Cost	95,468	77,628
Gross Unrealized Gains	287	55
Gross Unrealized (Losses)	(1,989)	(1,704)
Available for sale securities, Estimated fair value	93,766	75,979
Mortgage Backed Securities [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized Cost	561,466	544,823
Gross Unrealized Gains	8,502	6,127
Gross Unrealized (Losses)	(1,406)	(2,779)
Available for sale securities, Estimated fair value	568,562	548,171
Other Securities [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized Cost	11,085	11,085
Gross Unrealized Gains	27
Gross Unrealized (Losses)		(22)
Available for sale securities, Estimated fair value	$ 11,112	$ 11,063

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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- 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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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