Long-Term Debt (Other) (Details)								1 Months Ended	12 Months Ended
	Jun. 20, 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, 2018 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($) item	Mar. 31, 2018 USD ($)	May 31, 2017 USD ($)	Mar. 31, 2017 USD ($)
Long-Term Debt
Financing costs paid									$ 3,113,425	$ 99,785	$ 13,990,720
Drawdowns									261,000,000		676,819,873
Proceeds from sale of vessel											2,713,660
Presented as follows:
Total debt obligations													$ 775,164,186		$ 770,102,728
Less: deferred financing fees									20,138,480	23,748,116	23,748,116		16,061,034		20,138,480
Current portion of long-term debt													65,067,569		65,978,785
Long-term debt—net of current portion and deferred financing fees													694,035,583		683,985,463
Total													759,103,152		749,964,248
Long-term Debt, Other Disclosures [Abstract]
Deferred finance fees, beginning									20,138,480	23,748,116
Additions									3,255,859	99,785
Amortization									(7,506,509)	(3,709,421)	(2,499,185)
Gain early extinguishment of debt									173,204
Deferred finance fees, end									$ 16,061,034	$ 20,138,480	$ 23,748,116
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
Royal Bank of Scotland plc (RBS)
Long-Term Debt
Original loan amount								$ 135,224,500				$ 135,224,500
Number of tranches in which loan facility is divided | item												3
Presented as follows:
Total debt obligations															99,882,500
Tranche A
Presented as follows:
Total debt obligations															34,000,000
Tranche B
Presented as follows:
Total debt obligations															25,570,000
Tranche C
Presented as follows:
Total debt obligations															40,312,500
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													$ 546,654,871		670,220,228
2015 Debt Facility | LIBOR
Long-Term Debt
Interest Rate													2.29%
Commercial Financing
Long-Term Debt
Original loan amount								$ 249,000,000				$ 249,000,000
Term								7 years
Interest Rate													5.04%
Presented as follows:
Total debt obligations													$ 187,989,229		227,512,277
Commercial Financing | LIBOR
Long-Term Debt
Margin added to LIBOR for interest rate on loan facility (as a percent)								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													4.74%
Presented as follows:
Total debt obligations													$ 141,004,162		175,773,718
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													3.69%
Presented as follows:
Total debt obligations													$ 145,348,064		177,680,534
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													3.79%
Presented as follows:
Total debt obligations													$ 72,313,416		$ 89,253,699
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
The amount of restricted cash released							$ 6,000,000
Presented as follows:
Total debt obligations													66,940,405
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
Corsair Japanese Financing
Long-Term Debt
Stated rate (as a percent)						4.90%
Estimated financing cost to be incurred						$ 100,000
Monthly brokerage commission (as a percent)						1.25%
Brokerage commission fee on exercised purchase option excluding buyer deposit (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													50,645,833
Concorde Japanese Financing
Long-Term Debt
Stated rate (as a percent)				4.90%
Estimated financing cost to be incurred				$ 100,000
Monthly brokerage commission (as a percent)				1.25%
Brokerage commission fee on exercised purchase option excluding buyer deposit (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													55,192,308
Corvette Japanese Financing
Long-Term Debt
Stated rate (as a percent)			4.90%
Estimated financing cost to be incurred			$ 100,000
Monthly brokerage commission (as a percent)			1.25%
Brokerage commission fee on exercised purchase option excluding buyer deposit (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													$ 55,730,769