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Long-Term Debt (Condensed) (Details) - USD ($)						6 Months Ended
Long-Term Debt (Condensed) (Details) - USD ($)	Jun. 26, 2018	Jun. 25, 2018	Jun. 20, 2018	Jun. 11, 2018	Jun. 04, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Mar. 31, 2018	Jun. 08, 2017	Mar. 31, 2015
Debt obligations
Total debt obligations								$ 742,080,804	$ 775,164,186
Less: deferred financing fees						$ 16,061,034		15,544,668	16,061,034
Total								726,536,136	759,103,152
Presented as follows:
Current portion of long-term debt								63,968,414	65,067,569
Long-term debt—net of current portion and deferred financing fees								662,567,722	694,035,583
Total								726,536,136	759,103,152
Deferred financing fees
Deferred finance fees, beginning						16,061,034
Additions						1,080,848
Amortization						(1,597,214)	$ (2,898,375)
Deferred finance fees, end						$ 15,544,668
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
2017 Bridge Loan
Long-Term Debt
Original loan amount										$ 97,000,000
Repayment of debt			$ 44,600,000		$ 22,300,000
Debt obligations
Total debt obligations									66,940,405
2017 Bridge Loan \| CMNL LPG Transport LLC
Long-Term Debt
Repayment of debt			21,200,000
2017 Bridge Loan \| CNML LPG Transport LLC
Long-Term Debt
Repayment of debt			$ 23,400,000
Japanese Financings
Debt obligations
Total debt obligations								220,443,121	161,568,910
Corsair Japanese Financing
Debt obligations
Total debt obligations								49,020,833	50,645,833
Concorde Japanese Financing
Debt obligations
Total debt obligations								53,576,923	55,192,308
Corvette Japanese Financing
Debt obligations
Total debt obligations								54,115,385	55,730,769
CJNP Japanese Financing
Long-Term Debt
Stated rate (as a percent)				6.00%
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%
Principal payment frequency				monthly
Periodic principal payment amount				$ 100,000
Balloon payment amount				$ 13,000,000
Debt obligations
Total debt obligations								21,230,000
CMNL Japanese Financing
Long-Term Debt
Stated rate (as a percent)		6.00%
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%
Principal payment frequency		monthly
Periodic principal payment amount		$ 100,000
Balloon payment amount		$ 11,000,000
Debt obligations
Total debt obligations								20,130,942
CNML Japanese Financing
Long-Term Debt
Stated rate (as a percent)	6.00%
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%
Principal payment frequency	monthly
Periodic principal payment amount	$ 100,000
Balloon payment amount	$ 13,000,000
Debt obligations
Total debt obligations								22,369,038
2015 Debt Facility
Long-Term Debt
Original loan amount											$ 758,000,000
Debt obligations
Total debt obligations								521,637,683	546,654,871
Commercial Financing
Debt obligations
Total debt obligations								181,838,421	187,989,229
KEXIM Direct Financing
Debt obligations
Total debt obligations								133,432,153	141,004,162
KEXIM Guaranteed
Debt obligations
Total debt obligations								137,857,316	145,348,064
K-sure Insured
Debt obligations
Total debt obligations								$ 68,509,793	$ 72,313,416