Investments (Available for sale equity investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Debt Securities Trading And Equity Securities FvNi Cost [Abstract]
Amortized cost, equity investments	$ 54,748	$ 55,631
Estimated market value, equity investments	66,274	61,357
Common Stock [Member]
Debt Securities Trading And Equity Securities FvNi Cost [Abstract]
Amortized cost, equity investments	29,604	29,577
Estimated market value, equity investments	45,014	39,375
Nonredeemable Preferred Stock [Member]
Debt Securities Trading And Equity Securities FvNi Cost [Abstract]
Amortized cost, equity investments	25,144	26,054
Estimated market value, equity investments	$ 21,260	$ 21,982