Long-Term Debt (Other) (Details)											1 Months Ended	12 Months Ended
	Jun. 26, 2018 USD ($)	Jun. 25, 2018 USD ($)	Jun. 20, 2018 USD ($)	Jun. 11, 2018 USD ($)	Jun. 04, 2018 USD ($)	Mar. 16, 2018 USD ($)	Jan. 31, 2018 USD ($)	Dec. 08, 2017 USD ($)	Nov. 07, 2017 USD ($)	Jun. 08, 2017 USD ($)	Mar. 31, 2015 USD ($) item	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	May 31, 2017 USD ($)
Long-Term Debt
Financing costs paid												$ 40,547	$ 628,144	$ 3,113,425
Drawdowns													65,137,500	261,000,000
Presented as follows:
Total debt obligations																$ 646,128,204	$ 710,096,616
Less: deferred financing fees												11,152,985	14,005,830	16,061,034		11,152,985	14,005,830
Current portion of long-term debt																53,056,125	63,968,414
Long-term debt—net of current portion and deferred financing fees																581,919,094	632,122,372
Total																634,975,219	696,090,786
Long-term Debt, Other Disclosures [Abstract]
Deferred finance fees, beginning												14,005,830	16,061,034
Additions												40,547	1,080,847
Amortization												(2,893,392)	(3,136,051)	(7,506,509)
Deferred finance fees, end												$ 11,152,985	$ 14,005,830	$ 16,061,034
Corsair LPG Transport LLC
Long-Term Debt
Value of vessel transferred									$ 65,000,000
Term of Charter Agreement									12 years
Period until purchase option exercisable									2 years
Proceeds from sale of vessel									$ 52,000,000
Deposit retained by buyer									13,000,000
Concorde LPG Transport LLC
Long-Term Debt
Value of vessel transferred							$ 70,000,000
Term of Charter Agreement							13 years
Period until purchase option exercisable							3 years
Proceeds from sale of vessel							$ 56,000,000
Deposit retained by buyer							14,000,000
Corvette LPG Transport LLC
Long-Term Debt
Value of vessel transferred						$ 70,000,000
Term of Charter Agreement						13 years
Period until purchase option exercisable						3 years
Proceeds from sale of vessel						$ 56,000,000
Deposit retained by buyer						14,000,000
CJNP LPG Transport LLC
Long-Term Debt
Value of vessel transferred				$ 48,300,000
Term of Charter Agreement				6 years
Period until purchase option exercisable				2 years
Proceeds from sale of vessel				$ 21,700,000
Deposit retained by buyer				$ 26,600,000
CMNL LPG Transport LLC
Long-Term Debt
Value of vessel transferred		$ 45,800,000
Term of Charter Agreement		7 years
Period until purchase option exercisable		2 years
Proceeds from sale of vessel		$ 20,600,000
Deposit retained by buyer		$ 25,200,000
CNML LPG Transport LLC
Long-Term Debt
Value of vessel transferred	$ 50,800,000
Term of Charter Agreement	7 years
Period until purchase option exercisable	2 years
Proceeds from sale of vessel	$ 22,900,000
Deposit retained by buyer	$ 27,900,000
2015 Debt Facility
Long-Term Debt
Original loan amount											$ 758,000,000				$ 758,000,000
Number of tranches in which loan facility is divided | item											4
Number of VLGC newbuildings secured by loan | item											16
Loan-to-contract cost ratio before fees (as a percent)											55.00%
Commitment fee (as a percent)											40.00%
Repayment of debt						33,700,000	35,100,000
The amount of restricted cash released						$ 1,600,000	$ 1,600,000											$ 26,800,000
Presented as follows:
Total debt obligations																$ 446,586,121	496,620,495
2015 Debt Facility | LIBOR
Long-Term Debt
Interest Rate																1.23%
Commercial Financing
Long-Term Debt
Original loan amount											$ 249,000,000				$ 249,000,000
Term											7 years
Interest Rate																3.98%
Presented as follows:
Total debt obligations																$ 163,385,998	175,687,613
Commercial Financing | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)											2.75%	2.75%
Commercial Financing | 50% or more but less than 75% vessels financed are employed under time charters | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)											2.50%
Commercial Financing | 75% or more vessels financed are employed under time charters | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)											2.25%
Commercial Financing | Minimum | 50% or more but less than 75% vessels financed are employed under time charters
Long-Term Debt
Percent of vessels financed that are employed under time charters											50.00%				50.00%
Commercial Financing | Minimum | 75% or more vessels financed are employed under time charters
Long-Term Debt
Percent of vessels financed that are employed under time charters											75.00%				75.00%
Commercial Financing | Maximum | 50% or more but less than 75% vessels financed are employed under time charters
Long-Term Debt
Percent of vessels financed that are employed under time charters											75.00%				75.00%
KEXIM Direct Financing
Long-Term Debt
Original loan amount											$ 204,000,000				$ 204,000,000
Term											12 years
Interest Rate																3.68%
Presented as follows:
Total debt obligations																$ 110,716,127	125,860,144
KEXIM Direct Financing | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)															2.45%
KEXIM Guaranteed and K-sure Insured
Long-Term Debt
Original loan amount											$ 305,000,000				$ 305,000,000
KEXIM Guaranteed
Long-Term Debt
Original loan amount											$ 202,000,000				$ 202,000,000
Term											12 years
Interest Rate																2.63%
Presented as follows:
Total debt obligations																$ 115,385,072	130,366,568
KEXIM Guaranteed | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)															1.40%
K-sure Insured
Long-Term Debt
Original loan amount											$ 103,000,000				$ 103,000,000
Term											12 years
Interest Rate																2.73%
Presented as follows:
Total debt obligations																$ 57,098,924	64,706,170
K-sure Insured | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)															1.50%
2017 Bridge Loan
Long-Term Debt
Original loan amount										$ 97,000,000
Financing costs paid								$ 200,000
Repayment of debt			$ 44,600,000		$ 22,300,000				$ 30,100,000
2017 Bridge Loan | Period Ending December 7, 2017 | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)										2.50%
CMNL LPG Transport LLC
Long-Term Debt
Repayment of debt			23,400,000
CNML LPG Transport LLC
Long-Term Debt
Repayment of debt			$ 21,200,000
Japanese Financing Agreement [Member]
Presented as follows:
Total debt obligations																199,542,083	213,476,121
Corsair Japanese Financing
Long-Term Debt
Term of Charter Agreement									12 years
Stated rate (as a percent)									4.90%
Financing cost to be incurred									$ 100,000
Monthly brokerage commission (as a percent)									1.25%
Brokerage commission fee on exercised purchase option (as a percent)									1.00%
Periodic principal payment amount									$ 300,000
Principal payment frequency									monthly
Balloon payment amount									$ 13,000,000
Presented as follows:
Total debt obligations																44,145,833	47,395,833
Concorde Japanese Financing
Long-Term Debt
Stated rate (as a percent)							4.90%
Financing cost to be incurred							$ 100,000
Monthly brokerage commission (as a percent)							1.25%
Brokerage commission fee on exercised purchase option (as a percent)							1.00%
Periodic principal payment amount							$ 300,000
Principal payment frequency							monthly
Balloon payment amount							$ 14,000,000
Presented as follows:
Total debt obligations																48,730,769	51,961,538
Corvette Japanese Financing
Long-Term Debt
Stated rate (as a percent)						4.90%
Financing cost to be incurred						$ 100,000
Monthly brokerage commission (as a percent)						1.25%
Brokerage commission fee on exercised purchase option (as a percent)						1.00%
Periodic principal payment amount						$ 300,000
Principal payment frequency						monthly
Balloon payment amount						$ 14,000,000
Presented as follows:
Total debt obligations																49,269,231	52,500,000
CJNP Japanese Financing
Long-Term Debt
Stated rate (as a percent)				6.00%
Financing cost to be incurred				$ 100,000
Monthly brokerage commission (as a percent)				1.25%
Brokerage Commission Fee on delivery Purchase Option (as a percent)				0.50%
Brokerage commission fee on exercised purchase option (as a percent)				0.50%
Periodic principal payment amount				$ 100,000
Principal payment frequency				monthly
Balloon payment amount				$ 13,000,000
Presented as follows:
Total debt obligations																19,058,750	20,506,250
CMNL Japanese Financing
Long-Term Debt
Stated rate (as a percent)		6.00%
Financing cost to be incurred		$ 100,000
Monthly brokerage commission (as a percent)		1.25%
Brokerage Commission Fee on delivery Purchase Option (as a percent)		0.50%
Brokerage commission fee on exercised purchase option (as a percent)		0.50%
Periodic principal payment amount		$ 100,000
Principal payment frequency		monthly
Balloon payment amount		$ 11,000,000
Presented as follows:
Total debt obligations																18,076,488	19,446,131
CNML Japanese Financing
Long-Term Debt
Stated rate (as a percent)	6.00%
Financing cost to be incurred	$ 100,000
Monthly brokerage commission (as a percent)	1.25%
Brokerage Commission Fee on delivery Purchase Option (as a percent)	0.50%
Brokerage commission fee on exercised purchase option (as a percent)	0.50%
Periodic principal payment amount	$ 100,000
Principal payment frequency	monthly
Balloon payment amount	$ 13,000,000
Presented as follows:
Total debt obligations																$ 20,261,012	$ 21,666,369