ACQUISITIONS (Details) (USD $)	12 Months Ended	0 Months Ended	12 Months Ended
	Dec. 31, 2014	Jan. 17, 2014 item	Dec. 31, 2013	Dec. 31, 2012
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value:
Goodwill	$ 264,742,000		$ 256,871,000	$ 255,199,000
Information about the acquired loan portfolio
Estimated tax rate	25.90%
Minimum
Information about the acquired loan portfolio
Estimated useful life of core deposits intangible asset	8 years
Maximum
Information about the acquired loan portfolio
Estimated useful life of core deposits intangible asset	11 years
Acquisition of Bank of America Branches
MERGERS & ACQUISITIONS
Number of banking subsidiaries		20
Cash received		423,100,000
other costs		300,000
Percentage of premium on deposits received included in consideration paid		2.25%
Consideration Paid:
Cash consideration paid		17,105,000
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value:
Cash and short term investments		440,521,000
Loans		4,008,000
Premises and equipment		3,671,000
Core deposit intangibles		2,550,000
Other intangibles		(79,000)
Deposits		(440,522,000)
Other Liabilities		(944,000)
Total identifiable net assets		9,205,000
Goodwill		7,900,000
Carrying amount of impaired loans		201,000
Carrying amount of nonimpaired loans		4,300,000
Information about the acquired loan portfolio
Contractually required principal and interest at acquisition		201,000
Contractually cash flows not expected to be collected (nonaccretable discount)		(100,000)
Expected cash flows at acquisition		101,000
Interest component of expected cash flows (accretable premium)		20,000
Fair value of acquired loans		121,000
Acquisition related cost incurred	4,000,000		1,600,000
Estimated tax rate	40.50%		40.50%
Acquisition of Bank of America Branches | Core deposit intangible asset
Information about the acquired loan portfolio
Estimated useful life of core deposits intangible asset		9 years
Acquisition of Bank of America Branches | All other intangible assets
Information about the acquired loan portfolio
Estimated useful life of core deposits intangible asset		3 years
Acquisition of Bank of America Branches | As Acquired
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value:
Cash and short term investments		440,521,000
Loans		4,541,000
Premises and equipment		2,381,000
Deposits		(440,507,000)
Total identifiable net assets		6,936,000
Acquisition of Bank of America Branches | Fair Value Adjustments
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value:
Loans		(533,000)
Premises and equipment		1,290,000
Core deposit intangibles		2,550,000
Other intangibles		(79,000)
Deposits		(15,000)
Other Liabilities		(944,000)
Total identifiable net assets		$ 2,269,000