Vessel Operating Expenses (Details) - USD ($)	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Vessel Operating Expenses.
Crew wages and related costs	$ 41,649,202	$ 42,807,373	$ 43,724,030
Spares and stores	10,625,997	8,730,107	9,432,845
Insurance	3,452,874	3,758,485	4,668,838
Repairs and maintenance costs	5,594,957	4,028,775	3,867,993
Lubricants	3,206,445	2,677,177	2,742,944
Miscellaneous expenses	2,351,093	2,310,727	1,671,412
Total	$ 66,880,568	$ 64,312,644	$ 66,108,062

Represents the amount of expenses incurred on insurance.

No definition available.

Name:	lpg_CostOfInsurance
Namespace Prefix:	lpg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of expenses incurred on lubricants.

+ References

No definition available.

+ Details

Name:	lpg_CostOfLubricants
Namespace Prefix:	lpg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of expenses incurred on spares and stores.

+ References

No definition available.

+ Details

Name:	lpg_CostOfSparesAndStores
Namespace Prefix:	lpg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of vessel operating expenses incurred during the reported period.

+ References

No definition available.

+ Details

Name:	lpg_VesselOperatingExpenses
Namespace Prefix:	lpg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	lpg_VesselOperatingExpensesAbstract
Namespace Prefix:	lpg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

+ Details

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

- Definition

The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

+ Details

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

- Definition

Amount of expense for salary and wage arising from service rendered by nonofficer employee. Excludes allocated cost, labor-related nonsalary expense, and direct and overhead labor cost included in cost of good and service sold.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(4))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

+ Details

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