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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2016 USD ($) Subsidiary Trust Branch Component Calculation Segment Factor | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($)
Subsidiary, Sale of Stock [Line Items] |  |  |
Number of significant consolidated subsidiaries owned | Subsidiary | 2 |  |
Number of unconsolidated subsidiary business trusts owned | Trust | 2 |  |
Number of bank branches | Branch | 193 |  |
Number of counties in New York where the bank has facilities | Branch | 35 |  |
Number of counties in Pennsylvania where the bank has facilities | Branch | 6 |  |
Risks and Uncertainties [Abstract] |  |  |
Number of main components of economic risk | Component | 3 |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |
Period for which a nonaccrual TDR loan remains on nonaccrual status | 12 months |  |
Number of days past due for loans to be placed on nonaccrual status | 90 days |  |
Allowance for Loan Losses [Abstract] |  |  |
Number of broad components used in allowance methodology | Component | 2 |  |
Number of calculations used for general loan loss allocations | Calculation | 2 |  |
Number of main loan segments | Segment | 5 |  |
Period of historical net charge-off data for each loan class used in determining allowance level | 36 months |  |
Number of qualitative environmental factors used in qualitative calculation for general loan loss allocations | Factor | 8 |  |
Other Real Estate [Abstract] |  |  |
Other real estate | $ | $ 2.0 | $ 2.1 |
Advertising [Abstract] |  |  |
Advertising costs | $ | $ 3.9 | $ 3.6 | $ 3.2
Consumer Installment Loans [Member] |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |
Number of days past due after which loans are charged off to the extent outstanding principal balance exceeds fair value of collateral/property | 90 days |  |
Consumer Mortgage Loans [Member] |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |
Number of days past due after which loans are charged off to the extent outstanding principal balance exceeds fair value of collateral/property | 180 days |  |
Home Equity Loans [Member] |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |
Number of days past due after which loans are charged off to the extent outstanding principal balance exceeds fair value of collateral/property | 180 days |  |
Equipment [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 3 years |  |
Equipment [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 10 years |  |
Software [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 3 years |  |
Software [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 7 years |  |
Hardware [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 3 years |  |
Hardware [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 7 years |  |
Building and Building Improvements [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 10 years |  |
Building and Building Improvements [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 40 years |  |
Land Improvements [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Estimated useful life | 20 years |  |
BPAS [Member] |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Number of significant consolidated subsidiaries owned | Subsidiary | 4 |  |
Hand Benefits & Trust [Member] |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Number of significant consolidated subsidiaries owned | Subsidiary | 1 |  |
Core Deposits [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Intangible asset useful life (amortization period) | 7 years |  |
Core Deposits [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Intangible asset useful life (amortization period) | 20 years |  |
Customer Relationships [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Intangible asset useful life (amortization period) | 7 years |  |
Customer Relationships [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Intangible asset useful life (amortization period) | 20 years |  |
Commercial Portfolio Segment [Member] | Minimum [Member] |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |
Threshold balance of loans individually evaluated for impairment | $ | $ 0.5 |  |

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