ACQUISITIONS, Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of loans acquired [Abstract]
Merger and acquisition integration-related expenses	$ 1,706	$ 7,037	$ 123
EBS-RMSCO, Inc. [Member] | Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	8 years
EBS-RMSCO, 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
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