Note 4 - Long-term Debt (Details Textual)	12 Months Ended
Dec. 31, 2015 USD ($) a	Dec. 31, 2014 USD ($)
First Hawaiian Bank Revolving Line of Credit [Member] \| Honolua Store [Member]
Area of Real Estate Property \| a	1
First Hawaiian Bank Revolving Line of Credit [Member] \| Minimum [Member]
Debt Instrument, Covenant Required Liquidity	$ 3,000,000
First Hawaiian Bank Revolving Line of Credit [Member] \| Maximum [Member]
Debt Instrument Covenant Required Liabilities	175,000,000
First Hawaiian Bank Revolving Line of Credit [Member]
Line of Credit Facility, Commitment Fee Amount	0
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,500,000
Wells Fargo Revolving Loans [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	3.65%
Wells Fargo Revolving Loans [Member] \| Minimum [Member]
Debt Instrument, Covenant Required Liquidity	$ 3,000,000
Wells Fargo Revolving Loans [Member] \| Maximum [Member]
Debt Instrument Covenant Required Liabilities	175,000,000
Wells Fargo Revolving Loans [Member]
Line of Credit Facility, Commitment Fee Amount	0
Line of Credit Facility, Maximum Borrowing Capacity	$ 25,900,000
Pledged Assets not Separately Reported Area of Real Estate \| a	850
Long-term Debt	$ 25,868,000	$ 30,643,000
Debt Instrument, Interest Rate, Stated Percentage	4.00%	3.82%
American Ag Credit Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Interest Paid Monthly [Member]
Debt Instrument, Basis Spread on Variable Rate	3.75%
American Ag Credit Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Loan Balance Not Below $12.5 Million By April 1, 2016 [Member]
Debt Instrument, Basis Spread on Variable Rate	5.25%
American Ag Credit Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	6.75%
American Ag Credit Term Loan [Member] \| Minimum [Member] \| Loan Balance Not Below $12.5 Million By April 1, 2016 [Member]
Debt Instrument, Interest Rate, Stated Percentage	5.50%
American Ag Credit Term Loan [Member] \| Minimum [Member]
Debt Instrument, Covenant Required Liquidity	$ 3,000,000
American Ag Credit Term Loan [Member] \| Maximum [Member]
Debt Instrument Covenant Required Liabilities	$ 175,000,000
Debt Instrument, Mandatory Principal Repayments as Percentage Net Proceeds of Sale of Non Collateralized Real Property	75.00%
American Ag Credit Term Loan [Member] \| Maximum Balance for a 1.25% Decrease [Member]
Debt Instrument, Interest Rate, Increase (Decrease)	(1.25%)
Debt Instrument, Maximum Amount of Principal Balance Triggering Reduction in Interest Rate	$ 10,000,000
American Ag Credit Term Loan [Member] \| Maximum Balance for an Additional 1.25% Decrease [Member]
Debt Instrument, Interest Rate, Increase (Decrease)	(1.25%)
Debt Instrument, Maximum Amount of Principal Balance Triggering Reduction in Interest Rate	$ 5,000,000
American Ag Credit Term Loan [Member] \| Interest Paid Monthly [Member]
Debt Instrument, Interest Rate, Stated Percentage	4.00%
American Ag Credit Term Loan [Member] \| Maximum Balance on April 1, 2016 to Avoid an Additional .75% Increase [Member]
Debt Instrument, Maximum Amount of Principal Balance Triggering Reduction in Interest Rate	$ 12,500,000
American Ag Credit Term Loan [Member]
Pledged Assets not Separately Reported Area of Real Estate \| a	3,700
Long-term Debt	$ 14,697,000	$ 19,533,000
Debt Instrument, Interest Rate, Stated Percentage	7.00%	5.00%
Debt Instrument, Mandatory Principal Repayments as Percentage Net Proceeds of Sale of Real Estate Property Pledged as Collateral	100.00%
Minimum [Member]
Debt Instrument, Covenant Required Liquidity	$ 3,000,000
Maximum [Member]
Debt Instrument, Covenant Required Liquidity	175,000,000
Long-term Debt	$ 40,565,000	$ 50,176,000

Represents the amount of liabilities required to be maintained under financial covenants.

No definition available.

Name:	mlp_DebtInstrumentCovenantRequiredLiabilities
Namespace Prefix:	mlp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of liquidity required to be maintained under financial covenants.

+ References

No definition available.

+ Details

Name:	mlp_DebtInstrumentCovenantRequiredLiquidity
Namespace Prefix:	mlp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of mandatory principal repayment as a percentage of the net proceeds of the sale of non-collateralized real property.

+ References

No definition available.

+ Details

Name:	mlp_DebtInstrumentMandatoryPrincipalRepaymentsAsPercentageNetProceedsOfSaleOfNonCollateralizedRealProperty
Namespace Prefix:	mlp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of mandatory principal repayment as a percentage of the net proceeds of the sale of any real property pledged as collateral.

+ References

No definition available.

+ Details

Name:	mlp_DebtInstrumentMandatoryPrincipalRepaymentsAsPercentageNetProceedsOfSaleOfRealEstatePropertyPledgedAsCollateral
Namespace Prefix:	mlp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum principal amount outstanding to trigger reduction in interest rate.

+ References

No definition available.

+ Details

Name:	mlp_DebtInstrumentMaximumAmountOfPrincipalBalanceTriggeringReductionInInterestRate
Namespace Prefix:	mlp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Area of real estate owned but transferred to serve as collateral for the payment of the related debt obligation, primarily a secured borrowing or repurchase agreement, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

Name:	mlp_PledgedAssetsNotSeparatelyReportedAreaOfRealEstate
Namespace Prefix:	mlp_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Incremental percentage increase (decrease) in the stated rate on a debt instrument.

+ References

No definition available.

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mlp_FirstHawaiianBankRevolvingLineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CollateralAxis=mlp_HonoluaStoreMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mlp_WellsFargoRevolvingLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mlp_AmericanAgCreditTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=mlp_InterestPaidMonthlyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=mlp_LoanBalanceNotBelow125MillionByApril12016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=mlp_MaxiumumBalanceForA125PercentDecreaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=mlp_MaximumBalanceForAnAdditional125PercentDecreaseMember
Namespace Prefix:
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- Details

Name:	us-gaap_StatementScenarioAxis=mlp_MaximumBalanceOnApril12016ToAvoidAnAdditional75PercentIncreaseMember
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