Income Taxes (Provisions For Income Taxes By Location Of Taxing Jurisdiction) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Tax [Line Items]
Current income tax	$ 95,529	$ 45,857	$ 88,807
Deferred taxation (benefit) charge	1,293	(40)	(161)
Foreign tax credits generated-United States	(55,778)	(3,345)	(46,566)
Change in tax rate - United States	309
Income tax provision	41,353	42,472	42,080
South Africa [Member]
Income Tax [Line Items]
Current income tax	35,745	35,986	31,815
Deferred taxation (benefit) charge	2,528	(473)	3,044
United States [Member]
Income Tax [Line Items]
Current income tax	55,788	4,686	50,750
Deferred taxation (benefit) charge	477	1,123	(274)
Other [Member]
Income Tax [Line Items]
Current income tax	3,996	5,185	6,242
Deferred taxation (benefit) charge	$ (1,712)	$ (690)	$ (2,931)