Financial Instruments and Fair Value Disclosures (Carry and FV) (Details) - USD ($)	Jun. 30, 2018	Mar. 31, 2018
Financial instruments
Carry Value	$ 741,653,103	$ 759,103,152
Corsair Japanese Financing
Financial instruments
Carry Value	49,833,333	50,645,833
Corsair Japanese Financing | Level 2
Financial instruments
Fair Value	46,584,864	50,645,833
Concorde Japanese Financing
Financial instruments
Carry Value	54,384,615	55,192,308
Concorde Japanese Financing | Level 2
Financial instruments
Fair Value	50,574,308	55,192,308
Corvette Japanese Financing
Financial instruments
Carry Value	54,923,077	55,730,769
Corvette Japanese Financing | Level 2
Financial instruments
Fair Value	51,046,026	$ 55,730,769
CJNP Japanese Financing
Financial instruments
Carry Value	21,591,875
CJNP Japanese Financing | Level 2
Financial instruments
Fair Value	21,508,713
CMNL Japanese Financing
Financial instruments
Carry Value	20,473,363
CMNL Japanese Financing | Level 2
Financial instruments
Fair Value	20,395,106
CNML Japanese Financing
Financial instruments
Carry Value	22,720,387
CNML Japanese Financing | Level 2
Financial instruments
Fair Value	$ 22,629,188