Note 4 - Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Allowance for loan losses, beginning balance	$ 3,636	$ 3,298	$ 3,298
Allowance for loan losses, charge- offs	(16)		(848)
Allowance for loan losses, recoveries	36		104
Allowance for loan losses, provisions	70	60	1,082
Allowance for loan losses, ending balance	3,726		3,636
Allowance for loan losses: individually evaluated for impairment	17		17
Allowance for loan losses: collectively evaluated for impairment	3,709		3,619
Loans	428,043		418,991
Loans: individually evaluated for impairment	5,107		7,276
Loans: collectively evaluated for impairment	422,936		411,715
Construction Loan Portfolio Segment [Member] \| Residential [Member]
Allowance for loan losses, beginning balance	63	83	83
Allowance for loan losses, charge- offs
Allowance for loan losses, recoveries
Allowance for loan losses, provisions	4		(20)
Allowance for loan losses, ending balance	67		63
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	67		63
Loans	10,429		10,204
Loans: individually evaluated for impairment
Loans: collectively evaluated for impairment	10,429		10,204
Construction Loan Portfolio Segment [Member] \| Land Acquisition Development And Commercial [Member]
Allowance for loan losses, beginning balance	173	187	187
Allowance for loan losses, charge- offs			(2)
Allowance for loan losses, recoveries
Allowance for loan losses, provisions	22		(12)
Allowance for loan losses, ending balance	195		173
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	195		173
Loans	29,662		27,480
Loans: individually evaluated for impairment
Loans: collectively evaluated for impairment	29,662		27,480
Real Estate Portfolio Segment [Member] \| Residential [Member]
Allowance for loan losses, beginning balance	866	1,047	1,047
Allowance for loan losses, charge- offs			(4)
Allowance for loan losses, recoveries			45
Allowance for loan losses, provisions	38		(222)
Allowance for loan losses, ending balance	904		866
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	904		866
Loans	111,988		111,626
Loans: individually evaluated for impairment	769		770
Loans: collectively evaluated for impairment	111,219		110,856
Real Estate Portfolio Segment [Member] \| Commercial [Member]
Allowance for loan losses, beginning balance	1,516	1,001	1,001
Allowance for loan losses, charge- offs			(606)
Allowance for loan losses, recoveries	33
Allowance for loan losses, provisions	(22)		1,121
Allowance for loan losses, ending balance	1,527		1,516
Allowance for loan losses: individually evaluated for impairment	17		17
Allowance for loan losses: collectively evaluated for impairment	1,510		1,499
Loans	175,654		172,248
Loans: individually evaluated for impairment	4,309		6,495
Loans: collectively evaluated for impairment	171,345		165,753
Commercial Industrial and Agricultural Portfolio Segment [Member]
Allowance for loan losses, beginning balance	461	531	531
Allowance for loan losses, charge- offs			(34)
Allowance for loan losses, recoveries
Allowance for loan losses, provisions	7		(36)
Allowance for loan losses, ending balance	468		461
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	468		461
Loans	61,644		59,809
Loans: individually evaluated for impairment	29		11
Loans: collectively evaluated for impairment	61,615		59,798
Equity Lines Portfolio Segment [Member]
Allowance for loan losses, beginning balance	338	277	277
Allowance for loan losses, charge- offs			(99)
Allowance for loan losses, recoveries			10
Allowance for loan losses, provisions	(15)		150
Allowance for loan losses, ending balance	323		338
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	323		338
Loans	30,823		29,956
Loans: individually evaluated for impairment
Loans: collectively evaluated for impairment	30,823		29,956
Consumer Portfolio Segment [Member]
Allowance for loan losses, beginning balance	97	85	85
Allowance for loan losses, charge- offs	(16)		(103)
Allowance for loan losses, recoveries	3		49
Allowance for loan losses, provisions	11		66
Allowance for loan losses, ending balance	95		97
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	95		97
Loans	7,843		7,668
Loans: individually evaluated for impairment
Loans: collectively evaluated for impairment	7,843		7,668
Unallocated Financing Receivables [Member]
Allowance for loan losses, beginning balance	122	$ 87	87
Allowance for loan losses, charge- offs
Allowance for loan losses, recoveries
Allowance for loan losses, provisions	25		35
Allowance for loan losses, ending balance	147		122
Allowance for loan losses: individually evaluated for impairment
Allowance for loan losses: collectively evaluated for impairment	147		122
Loans
Loans: individually evaluated for impairment
Loans: collectively evaluated for impairment

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

Name:	us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for 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 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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 210.9-03.7(d))
-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 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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=82891408&loc=d3e4428-111522

+ Details

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

- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ Details

Name:	us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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