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ACQUISITIONS (Details) shares in Thousands, $ in Thousands |  |  |  |  | 3 Months Ended | 6 Months Ended
--- | --- | --- | --- | --- | --- | ---
Jun. 12, 2020 USD ($) Branch County shares | Sep. 18, 2019 USD ($) | Jul. 12, 2019 USD ($) Branch County | Jan. 02, 2019 USD ($) | Jun. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Jun. 30, 2020 USD ($) | Jun. 30, 2019 USD ($)
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Cash |  | $ 500 | $ 95,034 |  |  |  |  |  |
Loans acquired |  |  |  |  |  |  |  | $ 339,692 |
Investment securities |  |  | 39,770 |  |  |  |  |  |
Increase in deposits |  |  |  |  |  |  |  | 1,335,437 | $ 165,834
Customer Lists [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Intangibles |  | $ 500 |  |  |  |  |  |  |
Steuben [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Issuance of common shares (in shares) | shares | 1,360 |  |  |  |  |  |  |  |
Cash | $ 21,613 |  |  |  |  |  |  |  |
Assets acquired | 610,100 |  |  |  |  |  |  |  |
Loans acquired | 339,700 |  |  |  |  |  |  |  |
Investment securities | $ 180,497 |  |  |  |  |  |  |  |
Revenues |  |  |  |  | $ 600 |  |  | 600 |
Direct expenses |  |  |  |  | 300 |  |  | 300 |
Steuben [Member] | Western New York State [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Number of counties where the bank has facilities | County | 4 |  |  |  |  |  |  |  |
Number of new counties where the bank has extended footprints | County | 2 |  |  |  |  |  |  |  |
Number of branch locations | Branch | 11 |  |  |  |  |  |  |  |
Kinderhook Bank Corp [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Cash |  |  | $ 93,384 |  |  |  |  |  |
Number of branch locations | Branch |  |  | 11 |  |  |  |  |  |
Investment securities |  |  | $ 39,770 |  |  |  |  |  |
Increase in deposits |  |  |  |  |  |  | $ 80 |  |
Decrease in loans |  |  |  |  |  |  | (50) |  |
Increase (decrease) in other liabilities as a result of reclassification and adjustment |  |  |  |  |  | $ (300) | 40 |  |
Decrease in other assets |  |  |  |  |  |  | (40) |  |
Increased in accrued interest and fees receivable |  |  |  |  |  |  | 10 |  |
Increase (decrease) in goodwill as a result of fair value adjustment |  |  |  |  |  | $ (300) | $ 200 |  |
Kinderhook Bank Corp [Member] | Upstate New York [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Number of counties where the bank has facilities | County |  |  | 5 |  |  |  |  |  |
Assets acquired |  |  | $ 642,800 |  |  |  |  |  |
Investment securities |  |  | $ 39,800 |  |  |  |  |  |
Revenues |  |  |  |  | 4,400 |  |  | 8,900 |
Direct expenses |  |  |  |  | $ 1,700 |  |  | $ 3,600 |
Wealth Resources Network, Inc [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Cash |  |  |  | $ 1,200 |  |  |  |  |
Wealth Resources Network, Inc [Member] | Customer Lists [Member] |  |  |  |  |  |  |  |  |
Acquisitions [Abstract] |  |  |  |  |  |  |  |  |
Intangibles |  |  |  | $ 1,200 |  |  |  |  |

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