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ACQUISITIONS, Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Summary of loans acquired [Abstract] |  |  |
Merger and acquisition integration-related expenses | $ 25,986 | $ 1,706 | $ 7,037
Merchants Bancshares, Inc. [Member] | Core Deposits [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
Merchants Bancshares, Inc. [Member] | Other Intangibles [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
Dryfoos [Member] | Core Deposits [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
Dryfoos [Member] | Other Intangibles [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
BAS [Member] | Core Deposits [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
BAS [Member] | Other Intangibles [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
WJL Agencies Inc [Member] | Core Deposits [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
WJL Agencies Inc [Member] | Other Intangibles [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
Oneida Financial Corp [Member] | Core Deposits [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |
Oneida Financial Corp [Member] | Other Intangibles [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Estimated useful life | 8 years |  |

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460 + Details
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- References No definition available. + Details
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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