Income Taxes (Details) - U.S.	12 Months Ended
Mar. 31, 2018
Tax rate on US source shipping income (as a percent)	4.00%
Shipping income (as a percent)	50.00%

Represents the percentage of income attributable to transport of cargo to, or from foreign country.

No definition available.

Name:	lpg_PercentageOfShippingIncomeAttributableToTransportOfCargoToOrFromForeignCountry
Namespace Prefix:	lpg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration