Basis of Presentation and General Information (General) (Details)	12 Months Ended
Mar. 31, 2019 item
Basis of Presentation and General Information
Total number of vessels	23
Number of fuel-efficient ECO-design VLGCs having 84,000 cbm	19
Number of VLGCs having 82,000 cbm	3
Number of time chartered-in VLGC	1
The number of vessels that have exhaust gas cleaning systems	2
The number of vessels with contracts to purchase exhaust gas cleaning systems	10

Represents the number of fuel-efficient Eco-design Very Large Gas Carrier vessels in current fleet having a capacity of 84,000 cubic meters.

No definition available.

Name:	lpg_NumberOfFuelEfficientVeryLargeGasCarrierVesselsEightyFourThousandCapacity
Namespace Prefix:	lpg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The number of very large gas carrier VLGC time chartered-in vessels.

No definition available.

Name:	lpg_NumberOfVeryLargeGasCarrierTimeCharteredInVessels
Namespace Prefix:	lpg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the number of Very Large Gas Carrier vessels in current fleet having a capacity of 82,000 cubic meters.

No definition available.

Name:	lpg_NumberOfVeryLargeGasCarrierVesselsEightyTwoThousandCapacity
Namespace Prefix:	lpg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the total number of vessels owned by the entity.

No definition available.

The number of vessels that had contracts to purchase exhaust gas cleaning systems.

No definition available.

Name:	lpg_NumberOfVesselsThatHadContractsForExhaustGasCleaningScrubbersPurchases
Namespace Prefix:	lpg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of vessels that have exhaust gas cleaning systems.

No definition available.

Name:	lpg_NumberOfVesselsThatHaveExhaustGasCleaningScrubbers
Namespace Prefix:	lpg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

No definition available.

Name:	us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration