BORROWINGS, Contractual Maturity on Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Carrying value	$ 403,446	$ 440,122
Weighted-average rate at period end	1.05%
Weighted-average interest rate on borrowings during period	0.82%	0.89%
Federal Home Loan Bank Overnight Advance [Member]
Debt Instrument [Line Items]
Carrying value	$ 301,300	$ 338,000
Federal Home Loan Bank Overnight Advance [Member] \| January 4, 2016 [Member]
Debt Instrument [Line Items]
Carrying value	$ 301,300
Weighted-average rate at period end	0.52%
Subordinated Debt Held By Unconsolidated Subsidiary Trust [Member]
Debt Instrument [Line Items]
Carrying value	$ 102,146	$ 102,122
Subordinated Debt Held By Unconsolidated Subsidiary Trust [Member] \| July 31, 2031 [Member]
Debt Instrument [Line Items]
Carrying value	$ 24,826
Weighted-average rate at period end	3.91%
Subordinated Debt Held By Unconsolidated Subsidiary Trust [Member] \| December 15, 2036 [Member]
Debt Instrument [Line Items]
Carrying value	$ 77,320
Weighted-average rate at period end	2.16%

The average effective interest rate during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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