Note 4 - Loans Receivable - Delinquencies Within the Loan Portfolio (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Residential Portfolio Segment [Member] \| One-to-Four Family Loans [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	$ 1,621	$ 1,163
Residential Portfolio Segment [Member] \| One-to-Four Family Loans [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	1,000	951
Residential Portfolio Segment [Member] \| One-to-Four Family Loans [Member]
Past due	2,621	2,114
Current	113,586	116,019
Loans receivable	116,207	118,133	$ 109,005
Recorded investment > 90 days and still accruing		221
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	1,374	177
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	378	671
Commercial Real Estate Portfolio Segment [Member]
Past due	1,752	848
Current	199,096	167,082
Loans receivable	200,848	167,930	136,384
Recorded investment > 90 days and still accruing	4	4
Real Estate Construction Portfolio Segment [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	478	662
Real Estate Construction Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		247
Real Estate Construction Portfolio Segment [Member]
Past due	478	909
Current	15,904	22,049
Loans receivable	16,382	22,958	13,348
Recorded investment > 90 days and still accruing		247
Home Equity Portfolio Segment [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	433	319
Home Equity Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	288	161
Home Equity Portfolio Segment [Member]
Past due	721	480
Current	47,121	44,865
Loans receivable	47,842	45,345	41,511
Recorded investment > 90 days and still accruing
Consumer Portfolio Segment [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	126	184
Consumer Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	117	145
Consumer Portfolio Segment [Member]
Past due	243	329
Current	14,375	14,312
Loans receivable	14,618	14,641	14,480
Recorded investment > 90 days and still accruing
Commercial Portfolio Segment [Member] \| Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	125	173
Commercial Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	346	327
Commercial Portfolio Segment [Member]
Past due	471	500
Current	48,511	38,572
Loans receivable	48,982	39,072	44,247
Recorded investment > 90 days and still accruing	85
Financing Receivables, 30 to 89 Days Past Due [Member]
Past due	4,157	2,678
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	2,129	2,502
Past due	6,286	5,180
Current	438,593	402,899
Loans receivable	444,879	408,079	$ 358,975
Recorded investment > 90 days and still accruing	$ 89	$ 472

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5111-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing receivables that are current.

+ References

Reference 1: 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=66008989&loc=SL6953401-111524

+ Details

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

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

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=66008989&loc=SL6953401-111524

+ Details

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

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ebmt_OneToFourFamilyLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=ebmt_FinancingReceivables30To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ebmt_RealEstateConstructionPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ebmt_HomeEquityPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: