Note 13 - Employee Benefit Plans - Pension Plan Asset Allocation (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Target allocation	100.00%
Percentage of plan assets at year end	100.00%	100.00%
Expected rate of return on plan assets	6.75%	6.75%
Equity Securities [Member]
Target allocation	55.00%
Percentage of plan assets at year end	59.00%	56.00%
Expected rate of return on plan assets	5.15%
Debt Securities [Member]
Target allocation	37.00%
Percentage of plan assets at year end	40.00%	41.00%
Expected rate of return on plan assets	1.57%
Money Market Funds [Member]
Target allocation	8.00%
Percentage of plan assets at year end	1.00%	3.00%
Expected rate of return on plan assets	0.03%

This element represents the fair value of plan assets percentage.

No definition available.

Name:	emcf_DefinedBenefitPlanPlanAssetsAtFairValuePercentage
Namespace Prefix:	emcf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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- Details

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Data Type:	na
Balance Type:
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- Details

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