GOODWILL AND INTANGIBLE ASSETS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in carrying amount of goodwill
Balance at the beginning of the period	$ 64,900us-gaap_Goodwill	$ 63,947us-gaap_Goodwill
Acquired goodwill	8,550us-gaap_GoodwillAcquiredDuringPeriod	953us-gaap_GoodwillAcquiredDuringPeriod
Balance at the end of the period	73,450us-gaap_Goodwill	64,900us-gaap_Goodwill	63,947us-gaap_Goodwill
Goodwill
Goodwill impairment loss	0us-gaap_GoodwillImpairmentLoss
Acquired intangible assets
Accumulated amortization	(25,928)	(24,238)
Purchased intangibles, net	5,096	5,125
Aggregate amortization expense	1,690us-gaap_AmortizationOfIntangibleAssets	1,868us-gaap_AmortizationOfIntangibleAssets	1,835us-gaap_AmortizationOfIntangibleAssets
Estimated amortization expense
2015	1,599
2016	909
2017	541
2018	467
2019	354
Core deposit
Acquired intangible assets
Purchased intangibles, gross	28,830	27,169
Other customer relationship intangibles
Acquired intangible assets
Purchased intangibles, gross	$ 2,194	$ 2,194

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References