Fair Value Of Financial Instruments (Schedule Of Impact On Carrying Value Of Cell C Investment) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Jun. 30, 2021
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sensitivity for fair value of investment, increase (decrease) in valuation	$ 76,297	$ 76,297
3.3% Increase [Member] | Weighted Average Cost of Capital (WACC) Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sensitivity for fair value of investment, increase (decrease) in valuation	0
3.3% Increase [Member] | EBITDA Multiple [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sensitivity for fair value of investment, increase (decrease) in valuation	548
2.5% Decrease [Member] | Weighted Average Cost of Capital (WACC) Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sensitivity for fair value of investment, increase (decrease) in valuation	432
2.5% Decrease [Member] | EBITDA Multiple [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sensitivity for fair value of investment, increase (decrease) in valuation	$ 0