Investments (Available for sale equity investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Marketable Securities [Abstract]
Amortized cost, equity investments	$ 14,851	$ 14,851
Estimated market value, equity investments	21,199	25,125
Common stocks [Member]
Marketable Securities [Abstract]
Amortized cost, equity investments	9,775	9,775
Estimated market value, equity investments	16,595	20,015
Non-redeemable preferred stocks [Member]
Marketable Securities [Abstract]
Amortized cost, equity investments	5,076	5,076
Estimated market value, equity investments	$ 4,604	$ 5,110