XML 24 R33.htm IDEA: XBRL DOCUMENT
v2.4.1.9

LOANS (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items] |
Schedule of Loans Receivable, Net | The balances of these classes at December 31 are summarized as follows:
(000's omitted) |  | 2014 |  |  | 2013 |
Consumer mortgage |  | $ | 1,613,384 |  |  | $ | 1,582,058 |
Business lending |  |  | 1,262,484 |  |  |  | 1,260,364 |
Consumer indirect |  |  | 833,968 |  |  |  | 740,002 |
Consumer direct |  |  | 184,028 |  |  |  | 180,139 |
Home equity |  |  | 342,342 |  |  |  | 346,520 |
Gross loans, including deferred origination costs |  |  | 4,236,206 |  |  |  | 4,109,083 |
Allowance for loan losses |  |  | (45,341 | ) |  |  | (44,319 | )
Loans, net of allowance for loan losses |  | $ | 4,190,865 |  |  | $ | 4,064,764 |
Summary of Aggregate Amounts Loaned to Related Parties | Certain directors and executive officers of the Company, as well as associates of such persons, are loan customers. Loans to these individuals were made in the ordinary course of business under normal credit terms and do not have more than a normal risk of collection. Following is a summary of the aggregate amount of such loans during 2014 and 2013.
(000's omitted) |  | 2014 |  |  | 2013 |
Balance at beginning of year |  | $ | 9,448 |  |  | $ | 8,292 |
New loans |  |  | 1,647 |  |  |  | 3,643 |
Payments |  |  | (2,167 | ) |  |  | (2,487 | )
Balance at end of year |  | $ | 8,928 |  |  | $ | 9,448 |
Outstanding Principal Balance and Related Carrying Amount of Acquired Loans | Acquired loans Acquired loans are recorded at fair value as of the date of purchase with no allowance for loan loss. The outstanding principal balance and the related carrying amount of acquired loans included in the Consolidated Statement of Condition at December 31 are as follows:
(000's omitted) |  | 2014 |  |  | 2013 |
Credit impaired acquired loans: |  |  |  |  |  |
Outstanding principal balance |  | $ | 5,957 |  |  | $ | 11,457 |
Carrying amount |  |  | 5,312 |  |  |  | 7,090 |
Non-impaired acquired loans: |  |  |  |  |  |  |  |
Outstanding principal balance |  |  | 276,584 |  |  |  | 342,542 |
Carrying amount |  |  | 267,496 |  |  |  | 330,118 |
Total acquired loans: |  |  |  |  |  |  |  |
Outstanding principal balance |  |  | 282,541 |  |  |  | 353,999 |
Carrying amount |  |  | 272,808 |  |  |  | 337,208 |
Changes in Accretable Discount Related to Credit Impaired Acquired Loans | The outstanding balance related to credit impaired acquired loans was $6.1 million and $13.1 million at December 31, 2014 and 2013, respectively. The changes in the accretable discount related to the credit impaired acquired loans are as follows:
(000's omitted) |  | 2014 |  |  | 2013 |
Balance at beginning of year |  | $ | 997 |  |  | $ | 1,770 |
Accretion recognized |  |  | (707 | ) |  |  | (1,025 | )
Net reclassification to accretable from nonaccretable |  |  | 415 |  |  |  | 252 |
Balance at end of year |  | $ | 705 |  |  | $ | 997 |
Aged Analysis of Past Due Loans by Class | Management monitors the credit quality of its loan portfolio on an ongoing basis. Measurement of delinquency and past due status are based on the contractual terms of each loan. Past due loans are reviewed on a monthly basis to identify loans for non-accrual status. The following is an aged analysis of the Company’s past due loans by class as of December 31, 2014: Legacy Loans (excludes loans acquired after January 1, 2009)
(000’s omitted) |  | Past Due 30 - 89 days |  |  | 90+ Days Past Due and Still Accruing |  |  | Nonaccrual |  |  | Total Past Due |  |  | Current |  |  | Total Loans |
Consumer mortgage |  | $ | 13,978 |  |  | $ | 2,165 |  |  | $ | 13,201 |  |  | $ | 29,344 |  |  | $ | 1,515,057 |  |  | $ | 1,544,401 |
Business lending |  |  | 6,738 |  |  |  | 350 |  |  |  | 2,291 |  |  |  | 9,379 |  |  |  | 1,115,215 |  |  |  | 1,124,594 |
Consumer indirect |  |  | 10,529 |  |  |  | 82 |  |  |  | 10 |  |  |  | 10,621 |  |  |  | 822,124 |  |  |  | 832,745 |
Consumer direct |  |  | 1,389 |  |  |  | 36 |  |  |  | 2 |  |  |  | 1,427 |  |  |  | 177,158 |  |  |  | 178,585 |
Home equity |  |  | 1,802 |  |  |  | 195 |  |  |  | 2,172 |  |  |  | 4,169 |  |  |  | 278,904 |  |  |  | 283,073 |
Total |  | $ | 34,436 |  |  | $ | 2,828 |  |  | $ | 17,676 |  |  | $ | 54,940 |  |  | $ | 3,908,458 |  |  | $ | 3,963,398 |
Acquired Loans (includes loans acquired after January 1, 2009)
(000’s omitted) |  | Past Due 30 - 89 days |  |  | 90+ Days Past Due and Still Accruing |  |  | Nonaccrual |  |  | Total Past Due |  |  | Acquired Impaired(1) |  |  | Current |  |  | Total Loans |
Consumer mortgage |  | $ | 1,892 |  |  | $ | 232 |  |  | $ | 2,122 |  |  | $ | 4,246 |  |  | $ | 0 |  |  | $ | 64,737 |  |  | $ | 68,983 |
Business lending |  |  | 608 |  |  |  | 0 |  |  |  | 489 |  |  |  | 1,097 |  |  |  | 5,312 |  |  |  | 131,481 |  |  |  | 137,890 |
Consumer indirect |  |  | 40 |  |  |  | 0 |  |  |  | 0 |  |  |  | 40 |  |  |  | 0 |  |  |  | 1,183 |  |  |  | 1,223 |
Consumer direct |  |  | 174 |  |  |  | 0 |  |  |  | 18 |  |  |  | 192 |  |  |  | 0 |  |  |  | 5,251 |  |  |  | 5,443 |
Home equity |  |  | 674 |  |  |  | 46 |  |  |  | 426 |  |  |  | 1,146 |  |  |  | 0 |  |  |  | 58,123 |  |  |  | 59,269 |
Total |  | $ | 3,388 |  |  | $ | 278 |  |  | $ | 3,055 |  |  | $ | 6,721 |  |  | $ | 5,312 |  |  | $ | 260,775 |  |  | $ | 272,808 |
(1) | Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans.
The following is an aged analysis of the Company’s past due loans by class as of December 31, 2013: Legacy Loans (excludes loans acquired after January 1, 2009)
(000’s omitted) |  | Past Due 30 - 89 days |  |  | 90+ Days Past Due and Still Accruing |  |  | Nonaccrual |  |  | Total Past Due |  |  | Current |  |  | Total Loans |
Consumer mortgage |  | $ | 16,589 |  |  | $ | 1,253 |  |  | $ | 11,097 |  |  | $ | 28,939 |  |  | $ | 1,473,320 |  |  | $ | 1,502,259 |
Business lending |  |  | 2,960 |  |  |  | 164 |  |  |  | 3,083 |  |  |  | 6,207 |  |  |  | 1,079,818 |  |  |  | 1,086,025 |
Consumer indirect |  |  | 11,647 |  |  |  | 738 |  |  |  | 14 |  |  |  | 12,399 |  |  |  | 723,878 |  |  |  | 736,277 |
Consumer direct |  |  | 1,858 |  |  |  | 90 |  |  |  | 4 |  |  |  | 1,952 |  |  |  | 169,452 |  |  |  | 171,404 |
Home equity |  |  | 2,635 |  |  |  | 173 |  |  |  | 1,867 |  |  |  | 4,675 |  |  |  | 271,235 |  |  |  | 275,910 |
Total |  | $ | 35,689 |  |  | $ | 2,418 |  |  | $ | 16,065 |  |  | $ | 54,172 |  |  | $ | 3,717,703 |  |  | $ | 3,771,875 |
Acquired Loans (includes loans acquired after January 1, 2009)
(000’s omitted) |  | Past Due 30 - 89 days |  |  | 90+ Days Past Due and Still Accruing |  |  | Nonaccrual |  |  | Total Past Due |  |  | Acquired Impaired(1) |  |  | Current |  |  | Total Loans |
Consumer mortgage |  | $ | 1,857 |  |  | $ | 85 |  |  | $ | 1,463 |  |  | $ | 3,405 |  |  | $ | 0 |  |  | $ | 76,394 |  |  | $ | 79,799 |
Business lending |  |  | 531 |  |  |  | 0 |  |  |  | 1,472 |  |  |  | 2,003 |  |  |  | 7,090 |  |  |  | 165,246 |  |  |  | 174,339 |
Consumer indirect |  |  | 157 |  |  |  | 17 |  |  |  | 0 |  |  |  | 174 |  |  |  | 0 |  |  |  | 3,551 |  |  |  | 3,725 |
Consumer direct |  |  | 385 |  |  |  | 27 |  |  |  | 0 |  |  |  | 412 |  |  |  | 0 |  |  |  | 8,323 |  |  |  | 8,735 |
Home equity |  |  | 592 |  |  |  | 8 |  |  |  | 473 |  |  |  | 1,073 |  |  |  | 0 |  |  |  | 69,537 |  |  |  | 70,610 |
Total |  | $ | 3,522 |  |  | $ | 137 |  |  | $ | 3,408 |  |  | $ | 7,067 |  |  | $ | 7,090 |  |  | $ | 323,051 |  |  | $ | 337,208 |
(1) | Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans.
Summary of Impaired Loans, Excluding Purchased Impaired | All loan classes are collectively evaluated for impairment except business lending, as described in Note A. A summary of individually evaluated impaired loans as of December 31, 2014 and 2013 is as follows:
(000’s omitted) |  | 2014 |  |  | 2013 |
Loans with allowance allocation |  | $ | 0 |  |  | $ | 945 |
Loans without allowance allocation |  |  | 0 |  |  |  | 600 |
Carrying balance |  |  | 0 |  |  |  | 1,545 |
Contractual balance |  |  | 0 |  |  |  | 1,852 |
Specifically allocated allowance |  |  | 0 |  |  |  | 50 |
Average impaired loans |  |  | 0 |  |  |  | 10,729 |
Interest income recognized |  |  | 0 |  |  |  | 18 |
Information Regarding Troubled Debt Restructurings | Information regarding TDRs as of December 31, 2014 and December 31, 2013 is as follows
|  | December 31, 2014 |  |  | December 31, 2013 |
(000’s omitted) |  | Nonaccrual |  |  | Accruing |  |  | Total |  |  | Nonaccrual |  |  | Accruing |  |  | Total |
|  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |
Consumer mortgage |  |  | 49 |  |  | $ | 2,092 |  |  |  | 37 |  |  | $ | 1,770 |  |  |  | 86 |  |  | $ | 3,862 |  |  |  | 31 |  |  | $ | 1,682 |  |  |  | 48 |  |  | $ | 2,171 |  |  |  | 79 |  |  | $ | 3,853 |
Business lending |  |  | 6 |  |  |  | 442 |  |  |  | 3 |  |  |  | 468 |  |  |  | 9 |  |  |  | 910 |  |  |  | 4 |  |  |  | 162 |  |  |  | 1 |  |  |  | 47 |  |  |  | 5 |  |  |  | 209 |
Consumer indirect |  |  | 0 |  |  |  | 0 |  |  |  | 79 |  |  |  | 615 |  |  |  | 79 |  |  |  | 615 |  |  |  | 0 |  |  |  | 0 |  |  |  | 98 |  |  |  | 692 |  |  |  | 98 |  |  |  | 692 |
Consumer direct |  |  | 0 |  |  |  | 0 |  |  |  | 25 |  |  |  | 69 |  |  |  | 25 |  |  |  | 69 |  |  |  | 0 |  |  |  | 0 |  |  |  | 46 |  |  |  | 116 |  |  |  | 46 |  |  |  | 116 |
Home equity |  |  | 13 |  |  |  | 218 |  |  |  | 13 |  |  |  | 278 |  |  |  | 26 |  |  |  | 496 |  |  |  | 12 |  |  |  | 202 |  |  |  | 20 |  |  |  | 363 |  |  |  | 32 |  |  |  | 565 |
Total |  |  | 68 |  |  | $ | 2,752 |  |  |  | 157 |  |  | $ | 3,200 |  |  |  | 225 |  |  | $ | 5,952 |  |  |  | 47 |  |  | $ | 2,046 |  |  |  | 213 |  |  | $ | 3,389 |  |  |  | 260 |  |  | $ | 5,435 |
The following table presents information related to loans modified in a TDR during the years ended December 31, 2014 and 2013. Of the loans noted in the table below, all but three loans for the year ended December 31, 2014 and all but two loans for the year ended December 31, 2013, were modified due to a Chapter 7 bankruptcy as described previously. Of the three non-Chapter 7 bankruptcy TDRs in 2014 two relate to business loans restructured via granting a waiver of payments for a period of time and one was a business loan that was restructured via an extension of term. The 2013 non-Chapter 7 bankruptcy TDRs relate to a business loan restructured via an extension of term and a consumer mortgage restructured via an extension of term and a rate concession. The financial effects of these restructurings were immaterial.
|  | December 31, 2014 |  |  | December 31, 2013 |
(000’s omitted) |  |  | # |  |  | Amount |  |  |  | # |  |  | Amount |
Consumer mortgage |  |  | 22 |  |  | $ | 949 |  |  |  | 31 |  |  | $ | 1,758 |
Business lending |  |  | 7 |  |  |  | 769 |  |  |  | 3 |  |  |  | 183 |
Consumer indirect |  |  | 33 |  |  |  | 312 |  |  |  | 36 |  |  |  | 327 |
Consumer direct |  |  | 14 |  |  |  | 26 |  |  |  | 22 |  |  |  | 75 |
Home equity |  |  | 6 |  |  |  | 145 |  |  |  | 14 |  |  |  | 298 |
Total |  |  | 82 |  |  | $ | 2,201 |  |  |  | 106 |  |  | $ | 2,641 |
Activity in Allowance for Loan Losses by Class | The allowance for loan losses is general in nature and is available to absorb losses from any loan type despite the analysis below. The following presents by class the activity in the allowance for loan losses:
|  | Consumer |  |  | Business |  |  | Home |  |  | Consumer |  |  | Consumer |  |  |  |  |  | Acquired |  |  |  |
(000’s omitted) |  | Mortgage |  |  | Lending |  |  | Equity |  |  | Indirect |  |  | Direct |  |  | Unallocated |  |  | Impaired |  |  | Total |
Balance at December 31, 2012 |  | $ | 7,070 |  |  | $ | 18,013 |  |  | $ | 1,451 |  |  | $ | 9,606 |  |  | $ | 3,303 |  |  | $ | 2,666 |  |  | $ | 779 |  |  | $ | 42,888 |
Charge-offs |  |  | (1,012 | ) |  |  | (2,788 | ) |  |  | (650 | ) |  |  | (4,544 | ) |  |  | (1,954 | ) |  |  | 0 |  |  |  | (883 | ) |  |  | (11,831 | )
Recoveries |  |  | 36 |  |  |  | 692 |  |  |  | 20 |  |  |  | 3,488 |  |  |  | 1,034 |  |  |  | 0 |  |  |  | 0 |  |  |  | 5,270 |
Provision |  |  | 2,900 |  |  |  | 1,590 |  |  |  | 1,009 |  |  |  | 1,698 |  |  |  | 798 |  |  |  | (637 | ) |  |  | 634 |  |  |  | 7,992 |
Balance at December 31, 2013 |  |  | 8,994 |  |  |  | 17,507 |  |  |  | 1,830 |  |  |  | 10,248 |  |  |  | 3,181 |  |  |  | 2,029 |  |  |  | 530 |  |  |  | 44,319 |
Charge-offs |  |  | (1,075 | ) |  |  | (1,558 | ) |  |  | (765 | ) |  |  | (6,784 | ) |  |  | (1,595 | ) |  |  | 0 |  |  |  | (38 | ) |  |  | (11,815 | )
Recoveries |  |  | 205 |  |  |  | 750 |  |  |  | 85 |  |  |  | 3,773 |  |  |  | 846 |  |  |  | 0 |  |  |  | 0 |  |  |  | 5,659 |
Provision |  |  | 2,162 |  |  |  | (912 | ) |  |  | 1,551 |  |  |  | 4,307 |  |  |  | 651 |  |  |  | (262 | ) |  |  | (319 | ) |  |  | 7,178 |
Balance at December 31, 2014 |  | $ | 10,286 |  |  | $ | 15,787 |  |  | $ | 2,701 |  |  | $ | 11,544 |  |  | $ | 3,083 |  |  | $ | 1,767 |  |  | $ | 173 |  |  | $ | 45,341 |
Business Lending [Member] |
Accounts, Notes, Loans and Financing Receivable [Line Items] |
Schedule of Loans by Credit Quality Indicator | The following table shows the amount of business lending loans by credit quality category:
|  | December 31, 2014 |  |  | December 31, 2013 |
(000’s omitted) |  | Legacy |  |  | Acquired |  |  | Total |  |  | Legacy |  |  | Acquired |  |  | Total |
Pass |  | $ | 949,960 |  |  | $ | 93,510 |  |  | $ | 1,043,470 |  |  | $ | 908,885 |  |  | $ | 116,271 |  |  | $ | 1,025,156 |
Special mention |  |  | 103,176 |  |  |  | 18,038 |  |  |  | 121,214 |  |  |  | 93,600 |  |  |  | 24,264 |  |  |  | 117,864 |
Classified |  |  | 71,458 |  |  |  | 21,030 |  |  |  | 92,488 |  |  |  | 83,379 |  |  |  | 26,714 |  |  |  | 110,093 |
Doubtful |  |  | 0 |  |  |  | 0 |  |  |  | 0 |  |  |  | 161 |  |  |  | 0 |  |  |  | 161 |
Acquired impaired |  |  | 0 |  |  |  | 5,312 |  |  |  | 5,312 |  |  |  | 0 |  |  |  | 7,090 |  |  |  | 7,090 |
Total |  | $ | 1,124,594 |  |  | $ | 137,890 |  |  | $ | 1,262,484 |  |  | $ | 1,086,025 |  |  | $ | 174,339 |  |  | $ | 1,260,364 |
All Other Loans [Member] |
Accounts, Notes, Loans and Financing Receivable [Line Items] |
Schedule of Loans by Credit Quality Indicator | Legacy loans (excludes loans acquired after January 1, 2009)
(000’s omitted) |  | Consumer Mortgage |  |  | Consumer Indirect |  |  | Consumer Direct |  |  | Home Equity |  |  | Total |
Performing |  | $ | 1,529,035 |  |  |  | 832,653 |  |  |  | 178,547 |  |  |  | 280,706 |  |  | $ | 2,820,941 |
Nonperforming |  |  | 15,366 |  |  |  | 92 |  |  |  | 38 |  |  |  | 2,367 |  |  |  | 17,863 |
Total |  | $ | 1,544,401 |  |  | $ | 832,745 |  |  | $ | 178,585 |  |  | $ | 283,073 |  |  | $ | 2,838,804 |
Acquired loans (includes loans acquired after January 1, 2009)
(000’s omitted) |  | Consumer Mortgage |  |  | Consumer Indirect |  |  | Consumer Direct |  |  | Home Equity |  |  | Total |
Performing |  | $ | 66,629 |  |  |  | 1,223 |  |  |  | 5,425 |  |  |  | 58,797 |  |  | $ | 132,074 |
Nonperforming |  |  | 2,354 |  |  |  | 0 |  |  |  | 18 |  |  |  | 472 |  |  |  | 2,844 |
Total |  | $ | 68,983 |  |  | $ | 1,223 |  |  | $ | 5,443 |  |  | $ | 59,269 |  |  | $ | 134,918 |
The following table details the balances in all other loan categories at December 31, 2013: Legacy loans (excludes loans acquired after January 1, 2009)
(000’s omitted) |  | Consumer Mortgage |  |  | Consumer Indirect |  |  | Consumer Direct |  |  | Home Equity |  |  | Total |
Performing |  | $ | 1,489,909 |  |  | $ | 735,525 |  |  | $ | 171,310 |  |  | $ | 273,870 |  |  | $ | 2,670,614 |
Nonperforming |  |  | 12,350 |  |  |  | 752 |  |  |  | 94 |  |  |  | 2,040 |  |  |  | 15,236 |
Total |  | $ | 1,502,259 |  |  | $ | 736,277 |  |  | $ | 171,404 |  |  | $ | 275,910 |  |  | $ | 2,685,850 |
Acquired loans (includes loans acquired after January 1, 2009
(000’s omitted) |  | Consumer Mortgage |  |  | Consumer Indirect |  |  | Consumer Direct |  |  | Home Equity |  |  | Total |
Performing |  | $ | 78,251 |  |  | $ | 3,708 |  |  | $ | 8,708 |  |  | $ | 70,129 |  |  | $ | 160,796 |
Nonperforming |  |  | 1,548 |  |  |  | 17 |  |  |  | 27 |  |  |  | 481 |  |  |  | 2,073 |
Total |  | $ | 79,799 |  |  | $ | 3,725 |  |  | $ | 8,735 |  |  | $ | 70,610 |  |  | $ | 162,869 |

X
- Definition Tabular disclosure of changes to the aggregate cash flows related to loans expected to be collected over the investor's initial investment in the loan. This relates to loans with deteriorating of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References No definition available. + Details
Name: | cbu_ScheduleOfAccretableDiscountRelatedToCreditImpairedAcquiredLoansTableTextBlock
Namespace Prefix: | cbu_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of outstanding principal balance and the related carrying amount of acquired loans. + References No definition available. + Details
Name: | cbu_ScheduleOfOutstandingPrincipalBalanceRelatedCarryingAmountOfAcquiredLoansTextBlock
Namespace Prefix: | cbu_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition A tabular disclosure of related party transactions. Disclosure may include: the nature of the relationship(s), a description of the transactions, the amount of the transactions, the effects of any change in the method of establishing the terms of the transaction from the previous period, stated interest rate, expiration date, terms and manner of settlement per the agreement with the related party, revenues and expenses from related party transactions and amounts due to or from related parties. + References No definition available. + Details
Name: | cbu_ScheduleOfRelatedPartyTransactionsByRelatedPartyTableTextBlock
Namespace Prefix: | cbu_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of financing receivables (examples of financing receivables include loans, trade accounts receivable and notes receivable) and activity in the allowance for credit losses account. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524 + Details
Name: | us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of financing receivables by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 29 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953659-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 55 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=32702940&loc=SL6953803-111525 + Details
Name: | us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of impaired financing receivables. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivablesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of financing receivables that are past due but not impaired, financing receivables that are 90 days past due and still accruing, and financing receivables on nonaccrual status. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5111-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953401-111524 + Details
Name: | us-gaap_PastDueFinancingReceivablesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3,4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3, 4 -Article 5 + Details
Name: | us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of financing receivables and troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953682-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524 + Details
Name: | us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_ExcludingBusinessLendingLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |