Leases (assets and liabilities) (Details)	12 Months Ended
	Mar. 31, 2022 USD ($) item	Mar. 31, 2021 USD ($) item	Mar. 31, 2020 USD ($)
Leases
Number of option period for time charter | item	0	0
Operating lease income	$ 19,200,000	$ 29,100,000	$ 18,300,000
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]	Charter Hire Expenses	Charter Hire Expenses	Charter Hire Expenses
Lease term	12 months	12 months
Weighted average discount rate (as a percent)	3.88%
Weighted average remaining lease term	10 months
Operating lease right-of-use assets - Office Leases	$ 194,343
Operating lease right-of-use assets - Time Charter in VLGCs	7,892,671
Operating lease liabilities current - Office Leases	180,693
Operating lease liabilities current - Time Charter in VLGCs	$ 7,892,671
Minimum
Leases
Weighted average discount rate (as a percent)	3.82%
Maximum
Leases
Weighted average discount rate (as a percent)	5.53%