Short-Term Facilities (Narrative) (Details) $ in Thousands, € in Millions, SFr in Millions, R in Millions		1 Months Ended	12 Months Ended
		Feb. 28, 2017 USD ($)	Jun. 30, 2018 ZAR (R)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 29, 2018	Jan. 29, 2018 USD ($)	Jun. 30, 2017 EUR (€)	Jun. 30, 2017 CHF (SFr)	Jun. 30, 2017 ZAR (R)	Jun. 30, 2017 USD ($)
Short-term Debt [Line Items]
Amount utilized											$ 16,579	[1]
Value of shares issue		$ 45,000		$ 45,000
Bank Frick [Member] | United States [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity	[2]				10,000
Bank Frick [Member] | Europe [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity	[2]										66,579
Amount utilized	[2]										16,579
Nedbank Limited [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity					29,200						30,600
Amount utilized					7,871						10,000
South African Credit Facility [Member] | Nedbank Limited [Member]
Short-term Debt [Line Items]
Primary amount, available immediately			R 200.0		14,600
South African Credit Facility [Member] | Nedbank Limited [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity | R			150.0
Aggregate amount			400.0		29,200
Secondary amount, not available immediately			200.0		14,600
Amount utilized			R 108.0		7,900					R 130.5	10,000
Overdraft Facility [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity	[2]				$ 18,200						19,109
Overdraft Facility [Member] | Bank Frick [Member] | United States [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity							$ 10,000
Termination written notice			6 months
Interest rate			4.50%		4.50%
Overdraft Facility [Member] | Bank Frick [Member] | United States [Member] | LIBOR [Member]
Short-term Debt [Line Items]
Interest rate						2.31175%
Overdraft Facility [Member] | Nedbank Limited [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity			R 50.0		$ 3,600
Amount utilized					$ 0						0
Interest rate			8.85%		8.85%
Commitment fee percentage			0.35%
Revolving Overdraft Facility One [Member] | Bank Frick [Member] | Europe [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity | €								€ 40.0
Revolving Overdraft Facility Two [Member] | Bank Frick [Member] | Europe [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity | SFr									SFr 20.0
Amount utilized									SFr 15.9		16,600
Indirect And Derivative Facilities [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity					$ 11,000						11,491
Amount utilized					7,871						$ 10,000
Indirect And Derivative Facilities [Member] | Nedbank Limited [Member] | South Africa [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity			R 150.0		$ 11,000

[1] Refer to Note 1.

[2] Utilized amount included in short-term facilities on the consolidated balance sheets.