Note 4 - Long-term Debt (Details Textual) - First Hawaiian Bank Revolving Line of Credit [Member] - Revolving Credit Facility [Member] $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) ft² a
Line of Credit Facility, Maximum Borrowing Capacity	$ 15,000
Number of Optional Extension Periods	2
Line of Credit Facility, Extension Period	1 year
Line of Credit Facility, Commitment Fee Amount	$ 0
Debt Instrument, Covenant, Required Minimum Liquidity	1,500
Debt Instrument, Covenant, Maximum Total Liabilities	$ 45,000
Kapalua Mauka [Member]
Pledged Assets not Separately Reported, Area of Real Estate \| a	800
Kapalua Resort [Member]
Pledged Assets not Separately Reported, Area of Real Estate \| ft²	30,000
Minimum [Member]
Debt Instrument, Interest Rate, Effective Percentage	4.86%
Maximum [Member]
Debt Instrument, Interest Rate, Effective Percentage	4.37%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	3.50%

Represents the maximum total liabilities allowed under a debt instrument's covenant.

No definition available.

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

- Definition

Represents the minimum 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

Period of time between issuance and maturity of the optional extension period, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	mlp_LineOfCreditFacilityExtensionPeriod
Namespace Prefix:	mlp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of optional extension periods available under credit facilities that the company has.

+ References

No definition available.

+ Details

Name:	mlp_NumberOfOptionalExtensionPeriods
Namespace Prefix:	mlp_
Data Type:	xbrli:integerItemType
Balance Type:	na
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:	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

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
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

+ 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

+ Details

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

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=mlp_KapaluaMaukaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=mlp_KapaluaResortMember
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_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: