Note 9 - Income Taxes (Details Textual)	Mar. 31, 2018
Alternative Minimum Tax, Operating Loss Carryforwards Offset Percentage	100.00%

The percentage of income tax offset due to the alternative minimum tax operating loss carryforwards.

No definition available.

Name:	mlp_AlternativeMinimumTaxOperatingLossCarryforwardsOffsetPercentage
Namespace Prefix:	mlp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant