Borrowings (Summary Of Short-Term Credit Facilities) (Details) $ in Thousands, R in Millions, ₩ in Billions		3 Months Ended		6 Months Ended
		Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 ZAR (R)	Dec. 31, 2018 USD ($)	Feb. 04, 2019 USD ($)	Jan. 01, 2019 KRW (₩)	Jan. 01, 2019 USD ($)	Sep. 14, 2018 USD ($)
Short-term Debt [Line Items]
Utilized		$ 207,876	$ 221,582	$ 391,550		$ 306,237
Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Short-term facility available		103,215		103,215
Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		32,213		32,213
Balance as of June 30, 2019				84,990
Utilized				391,550
Repaid				(378,554)
Foreign currency adjustment	[1]			280
Balance as of September 30, 2019		98,266		98,266
Overdraft Facility [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		84,360		84,360
Overdraft Facility [Member] | No Restrictions As To Use [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		13,906		13,906
Indirect And Derivative Facilities [Member]
Short-term Debt [Line Items]
Short-term facility available		10,677		10,677
Balance as of June 30, 2019				6,643
Guarantees cancelled				0
Utilized				0
Foreign currency adjustment				17
Balance as of September 30, 2019		6,660		6,660
South Africa [Member] | Amended July 2017 [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Short-term facility available		85,419		85,419
South Africa [Member] | Amended July 2017 [Member] | Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
Balance as of June 30, 2019				69,566
Utilized				349,466
Repaid				(346,525)
Foreign currency adjustment	[1]			157
Balance as of September 30, 2019		72,664		72,664
South Africa [Member] | Amended July 2017 [Member] | Overdraft Facility [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		72,664		72,664
South Africa [Member] | Amended July 2017 [Member] | Overdraft Facility [Member] | No Restrictions As To Use [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		0		0
South Africa [Member] | Amended July 2017 [Member] | Indirect And Derivative Facilities [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
Balance as of June 30, 2019				0
Guarantees cancelled				0
Utilized				0
Foreign currency adjustment	[1]			0
Balance as of September 30, 2019		0		0
South Africa [Member] | Nedbank Limited [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Short-term facility available		17,796		17,796
South Africa [Member] | Nedbank Limited [Member] | Nedbank Short-Term Credit Facility [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		11,700		11,700
South Africa [Member] | Nedbank Limited [Member] | Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		3,559		3,559
Balance as of June 30, 2019				5,880
Utilized				33,722
Repaid				(28,029)
Foreign currency adjustment	[1]			123
Balance as of September 30, 2019		11,696		11,696
South Africa [Member] | Nedbank Limited [Member] | Overdraft Facility [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		11,696		11,696
South Africa [Member] | Nedbank Limited [Member] | Overdraft Facility [Member] | No Restrictions As To Use [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		0		0
South Africa [Member] | Nedbank Limited [Member] | Overdraft Facility [Member] | Nedbank Short-Term Credit Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		14,400		14,400
Total overdraft facilities withdrawn				14,400
South Africa [Member] | Nedbank Limited [Member] | Indirect And Derivative Facilities [Member]
Short-term Debt [Line Items]
Short-term facility available		10,677		10,677
Balance as of June 30, 2019				6,643
Guarantees cancelled				0
Utilized				0
Foreign currency adjustment	[1]			17
Balance as of September 30, 2019		6,660		6,660
South Africa [Member] | Nedbank Limited [Member] | Indirect And Derivative Facilities [Member] | Nedbank Short-Term Credit Facility [Member]
Short-term Debt [Line Items]
Balance as of June 30, 2019				6,600	R 93.6
Balance as of September 30, 2019		6,700		6,700	R 93.6
United States [Member] | Bank Frick [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
United States [Member] | Bank Frick [Member] | Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		20,000		20,000			$ 20,000
Balance as of June 30, 2019				9,544
Utilized				8,362
Repaid				(4,000)
Foreign currency adjustment	[1]			0
Balance as of September 30, 2019		13,906		13,906
United States [Member] | Bank Frick [Member] | Overdraft Facility [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		0		0
United States [Member] | Bank Frick [Member] | Overdraft Facility [Member] | No Restrictions As To Use [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		13,906		13,906
United States [Member] | Bank Frick [Member] | Indirect And Derivative Facilities [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
Balance as of June 30, 2019				0
Guarantees cancelled				0
Utilized				0
Foreign currency adjustment				0
Balance as of September 30, 2019		0		0
United States [Member] | Bank Frick [Member] | Renewed [Member] | Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available										$ 10,000
Balance as of September 30, 2019		13,900		13,900
South Korea [Member] | Hana Bank [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
South Korea [Member] | Hana Bank [Member] | Overdraft Facility [Member]
Short-term Debt [Line Items]
Short-term facility available		8,654		8,654				₩ 10.0	$ 8,700
Balance as of June 30, 2019				0
Utilized				0
Repaid				0
Foreign currency adjustment	[1]			0
Balance as of September 30, 2019		0		0
South Korea [Member] | Hana Bank [Member] | Overdraft Facility [Member] | Overdraft Restricted As To Use For ATM Funding Only [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		0		0
South Korea [Member] | Hana Bank [Member] | Overdraft Facility [Member] | No Restrictions As To Use [Member]
Short-term Debt [Line Items]
Balance as of September 30, 2019		0		0
South Korea [Member] | Hana Bank [Member] | Indirect And Derivative Facilities [Member]
Short-term Debt [Line Items]
Short-term facility available		0		0
Balance as of June 30, 2019				0
Guarantees cancelled				0
Utilized				0
Foreign currency adjustment				0
Balance as of September 30, 2019		$ 0		$ 0

[1] Represents the effects of the fluctuations between the ZAR and the U.S. dollar.