XML 61 R50.htm IDEA: XBRL DOCUMENT
v3.22.2

LEASES - Narrative (Details) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease, weighted average remaining lease term (years) | 9 years 3 days |  | 9 years 3 days |
Operating lease, weighted average discount rate | 3.34% |  | 3.34% |
Operating lease, rent expense | $ 200,000 |  | $ 500,000 |
Operating lease not yet commenced | $ 0 |  | $ 0 |
Finance lease, weighted average remaining lease term (years) | 10 years 8 months 4 days |  | 10 years 8 months 4 days |
Finance lease, weighted average discount rate | 3.38% |  | 3.38% |
Finance lease not yet commenced | $ 0 |  | $ 0 |
1365 New Scotland Road, Slingerlands, New York | Director |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease, rent expense |  |  | 13,000 | $ 12,000
Monthly rent and common area maintenance expense |  |  | 4,000 |
Rent and common area maintenance expense |  |  | 25,000 | 25,000
2 Rush Street, Schenectady, New York | Director |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease, rent expense | $ 25,000 | $ 24,000 |  |
Monthly rent and common area maintenance expense |  |  | 8,000 |
Rent and common area maintenance expense |  |  | $ 51,000 | $ 50,000

X
- Definition Lessee, Finance Lease, Lease Not yet Commenced, Liability + References No definition available. + Details
Name: | chmg_LesseeFinanceLeaseLeaseNotYetCommencedLiability
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Lessee, Operating Lease, Lease Not yet Commenced, Liability + References No definition available. + Details
Name: | chmg_LesseeOperatingLeaseLeaseNotYetCommencedLiability
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating Lease, Monthly Rent And Common Area Maintenance Expense + References No definition available. + Details
Name: | chmg_OperatingLeaseMonthlyRentAndCommonAreaMaintenanceExpense
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating Lease, Rent And Common Area Maintenance Expense + References No definition available. + Details
Name: | chmg_OperatingLeaseRentAndCommonAreaMaintenanceExpense
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average discount rate for finance lease calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(4) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of operating lease expense. Excludes sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 4 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918638-209977 + Details
Name: | us-gaap_OperatingLeaseExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average discount rate for operating lease calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(4) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=chmg_BranchLocation1365NewScotlandRoadSlingerlandsNewYorkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_DirectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=chmg_BranchLocation2RushStreetSchenectadyNewYorkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |