Investments (Available for sale equity investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Marketable Securities [Abstract]
Amortized cost, equity investments	$ 53,728	$ 29,809
Estimated market value, equity investments	72,307	42,117
Common stocks [Member]
Marketable Securities [Abstract]
Amortized cost, equity investments	27,674	9,775
Estimated market value, equity investments	46,212	20,440
Non-redeemable preferred stocks [Member]
Marketable Securities [Abstract]
Amortized cost, equity investments	26,054	20,034
Estimated market value, equity investments	$ 26,095	$ 21,677