Note 5 - Loans (Details) - Composition of Impaired Loans by Class (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	$ 19,275	$ 20,426
Impaired loans with no related allowance, unpaid principal balance	21,696	27,175
With an allowance recorded:
Impaired loans with related allowance, recorded investment	9,440	11,136
Impaired loans with related allowance, unpaid principal balance	10,894	12,971
Impaired loans, related allowance	1,440	1,737
Total:
Impaired loans, recorded investment	28,715	31,562
Impaired loans, unpaid principal balance	32,590	40,146
Impaired loans, related allowance	1,440	1,737
Construction, Land Development and Other Land Loan [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	185	283
Impaired loans with no related allowance, unpaid principal balance	185	805
With an allowance recorded:
Impaired loans with related allowance, recorded investment	101	6
Impaired loans with related allowance, unpaid principal balance	101	6
Total:
Impaired loans, recorded investment	286	289
Impaired loans, unpaid principal balance	286	811
Non Farm Nonresidential [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	18,077	18,534
Impaired loans with no related allowance, unpaid principal balance	19,044	23,055
With an allowance recorded:
Impaired loans with related allowance, recorded investment	8,358	10,186
Impaired loans with related allowance, unpaid principal balance	9,812	12,021
Impaired loans, related allowance	1,254	1,555
Total:
Impaired loans, recorded investment	26,435	28,720
Impaired loans, unpaid principal balance	28,856	35,076
Impaired loans, related allowance	1,254	1,555
Commercial Real Estate Loans [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	18,262	18,817
Impaired loans with no related allowance, unpaid principal balance	19,229	23,860
With an allowance recorded:
Impaired loans with related allowance, recorded investment	8,459	10,192
Impaired loans with related allowance, unpaid principal balance	9,913	12,027
Impaired loans, related allowance	1,254	1,555
Total:
Impaired loans, recorded investment	26,721	29,009
Impaired loans, unpaid principal balance	29,142	35,887
Impaired loans, related allowance	1,254	1,555
Single-family Real Estate, Revolving, Open-end Loans [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment		333
Impaired loans with no related allowance, unpaid principal balance		333
Total:
Impaired loans, recorded investment		333
Impaired loans, unpaid principal balance		333
Single Family Residential Closed End First Lien [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	564	645
Impaired loans with no related allowance, unpaid principal balance	668	750
With an allowance recorded:
Impaired loans with related allowance, recorded investment	256	208
Impaired loans with related allowance, unpaid principal balance	256	208
Impaired loans, related allowance	28	24
Total:
Impaired loans, recorded investment	820	853
Impaired loans, unpaid principal balance	924	958
Impaired loans, related allowance	28	24
Single Family Residential Closed End Junior Lien [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	23	24
Impaired loans with no related allowance, unpaid principal balance	23	24
With an allowance recorded:
Impaired loans with related allowance, recorded investment	104	106
Impaired loans with related allowance, unpaid principal balance	104	106
Impaired loans, related allowance	40	41
Total:
Impaired loans, recorded investment	127	130
Impaired loans, unpaid principal balance	127	130
Impaired loans, related allowance	40	41
Single Family Residential [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	587	1,002
Impaired loans with no related allowance, unpaid principal balance	691	1,107
With an allowance recorded:
Impaired loans with related allowance, recorded investment	360	314
Impaired loans with related allowance, unpaid principal balance	360	314
Impaired loans, related allowance	68	65
Total:
Impaired loans, recorded investment	947	1,316
Impaired loans, unpaid principal balance	1,051	1,421
Impaired loans, related allowance	68	65
Commercial and Industrial [Member]
With no related allowance recorded:
Impaired loans with no related allowance, recorded investment	426	607
Impaired loans with no related allowance, unpaid principal balance	1,776	2,208
With an allowance recorded:
Impaired loans with related allowance, recorded investment	607	616
Impaired loans with related allowance, unpaid principal balance	607	616
Impaired loans, related allowance	116	115
Total:
Impaired loans, recorded investment	1,033	1,223
Impaired loans, unpaid principal balance	2,383	2,824
Impaired loans, related allowance	116	115
Consumer [Member]
With an allowance recorded:
Impaired loans with related allowance, recorded investment	14	14
Impaired loans with related allowance, unpaid principal balance	14	14
Impaired loans, related allowance	2	2
Total:
Impaired loans, recorded investment	14	14
Impaired loans, unpaid principal balance	14	14
Impaired loans, related allowance	$ 2	$ 2

Name:	plmt_TotalAbstract
Namespace Prefix:	plmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	plmt_WithAnAllowanceRecordedAbstract
Namespace Prefix:	plmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	plmt_WithNoRelatedAllowanceRecordedAbstract
Namespace Prefix:	plmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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