XML 60 R48.htm IDEA: XBRL DOCUMENT v3.7.0.1

SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		$ 38,276
Excess collateral held	$ (9,014)	(10,670)
Gross amount of recognized liabilities for repurchase agreements	11,937	27,606
Obligations of U.S. Government and U.S. Government sponsored enterprises
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		1,276
Mortgage-backed securities, residential
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase	20,951	37,000
Overnight and Continuous
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		13,092
Excess collateral held	(5,925)	(5,486)
Gross amount of recognized liabilities for repurchase agreements	1,937	7,606
Overnight and Continuous | Obligations of U.S. Government and U.S. Government sponsored enterprises
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		0
Overnight and Continuous | Mortgage-backed securities, residential
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase	7,862	13,092
Up to 1 Year
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		10,940
Excess collateral held	(3,089)	(940)
Gross amount of recognized liabilities for repurchase agreements	10,000	10,000
Up to 1 Year | Obligations of U.S. Government and U.S. Government sponsored enterprises
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		1,276
Up to 1 Year | Mortgage-backed securities, residential
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase	13,089	9,664
1 - 3 Years
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		14,244
Excess collateral held	0	(4,244)
Gross amount of recognized liabilities for repurchase agreements	0	10,000
1 - 3 Years | Obligations of U.S. Government and U.S. Government sponsored enterprises
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		0
1 - 3 Years | Mortgage-backed securities, residential
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase	0	14,244
3 Years
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		0
Excess collateral held	0	0
Gross amount of recognized liabilities for repurchase agreements	0	0
3 Years | Obligations of U.S. Government and U.S. Government sponsored enterprises
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase		0
3 Years | Mortgage-backed securities, residential
Summary of securities sold under agreements to repurchase [Abstract]
Securities sold under agreements to repurchase	$ 0	$ 0

X

- References

No definition available.

+ Details

Name:	chmg_SummaryOfSecuritiesSoldUnderAgreementsToRepurchaseAbstract
Namespace Prefix:	chmg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(a)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(1))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=49176635&loc=d3e9760-107771

+ Details

Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchase
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value of securities pledged as collateral against securities sold under agreement to repurchase.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226013-175313

+ Details

Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226000-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis=us-gaap_MaturityOvernightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis=chmg_MaturityUpToOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis=chmg_AfterOneYearButWithinThreeYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis=chmg_AfterThreeYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: