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BENEFIT PLANS, Fair Value of Plan Assets by Assets Category (Details) - USD ($) $ in Thousands | 2 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 01, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [1] |  | $ 180,086 | $ 171,625 |
Total dividends and interest receivable excluded from plan assets |  |  | 300 | 400 |
Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [1] |  | 166,117 | 159,324 |
Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [1] |  | 13,969 | 12,301 |
Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [1] |  | 0 | 0 |
Money Market Accounts [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 8,151 | 7,990 |
Money Market Accounts [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 103 | 2,240 |
Money Market Accounts [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 8,048 | 5,750 |
Money Market Accounts [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Equity Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 96,748 | 83,868 |
Equity Securities [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 96,748 | 83,868 |
Equity Securities [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Equity Securities [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
U.S. Large-Cap [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 43,235 | 34,985 |
U.S. Large-Cap [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 43,235 | 34,985 |
U.S. Large-Cap [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
U.S. Large-Cap [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
U.S Mid/Small Cap [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 19,032 | 12,354 |
U.S Mid/Small Cap [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 19,032 | 12,354 |
U.S Mid/Small Cap [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
U.S Mid/Small Cap [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
CBSI Stock [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 7,417 | 8,393 |
CBSI Stock [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 7,417 | 8,393 |
CBSI Stock [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
CBSI Stock [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
International [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 27,064 | 28,136 |
International [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 27,064 | 28,136 |
International [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
International [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Fixed Income Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 63,106 | 69,767 |
Fixed Income Securities [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 57,243 | 63,279 |
Fixed Income Securities [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 5,863 | 6,488 |
Fixed Income Securities [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Government Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 31,238 | 37,885 |
Government Securities [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 25,375 | 31,397 |
Government Securities [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 5,863 | 6,488 |
Government Securities [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Investment Grade Bonds [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 15,253 | 14,517 |
Investment Grade Bonds [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 15,253 | 14,517 |
Investment Grade Bonds [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
Investment Grade Bonds [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 0 | 0 |
International Bonds [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  |  | 5,085 |
International Bonds [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  |  | 5,085 |
International Bonds [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  |  | 0 |
International Bonds [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  |  | 0 |
High Yield [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [2] |  | 16,615 | 17,365 |
High Yield [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [2] |  | 16,615 | 17,365 |
High Yield [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [2] |  | 0 | 0 |
High Yield [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [2] |  | 0 | 0 |
Other Investments [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [3] |  | 12,081 | 10,000 |
Other Investments [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [3] |  | 12,023 | 9,937 |
Other Investments [Member] | Significant Observable Inputs, Level 2 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [3] |  | 58 | 63 |
Other Investments [Member] | Significant Unobservable Inputs, Level 3 [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets | [3] |  | 0 | 0 |
State Bank of Chittenango Pension Plan [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Employer contributions |  |  | 0 |  |
Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Fair value of plan assets |  |  | 180,400 | 172,026 | $ 177,865
Employer contributions |  |  | $ 2,146 | $ 616 |
Subsequent Event [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Employer contributions |  | $ 2,900 |  |  |
[1] | Excludes dividends and interest receivable totaling $0.3 million and $0.4 million at December 31, 2016 and 2015, respectively.
[2] | This category is exchange-traded funds representing a diversified index of high yield corporate bonds.
[3] | This category is comprised of exchange-traded funds and mutual funds holding non-traditional investment classes including private equity funds and alternative exchange funds.

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- Definition Represents the total of interest and dividend receivable, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein. + References No definition available. + Details
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