Leases (Charter hire expenses) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Time Charter-in
Charter hire expenses	$ 2,403,968	$ 4,518,850	$ 5,912,038	$ 9,234,448