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ACQUISITIONS, Acquisitions of Oneida, EBS-RMSCO and B of A (Details) shares in Thousands, $ in Thousands | Dec. 04, 2015 USD ($) Branch shares | Jan. 02, 2014 USD ($) | Dec. 13, 2013 USD ($) Branch
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EBS-RMSCO, Inc. [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Deposits acquired |  | $ 0 |
Bank of America Agreement [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Number of new branch locations included in acquisition or purchase agreement | Branch |  |  | 8
Deposits acquired |  |  | $ 303,456
Blended deposit premium |  |  | 2.40%
Total deposit premium paid |  |  | $ 7,300
Bank of America Agreement [Member] | Core Deposits [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Deposits acquired |  |  | 220,000
Bank of America Agreement [Member] | Time Deposits [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Deposits acquired |  |  | $ 83,000
Oneida Financial Corp [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Cash/Total net consideration paid | $ 158,000 |  |
Issuance of common shares (in shares) | shares | 2,780 |  |
Number of new branch locations included in acquisition or purchase agreement | Branch | 12 |  |
Assets acquired | $ 769,000 |  |
Deposits acquired | $ 699,241 |  |

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