Basis Of Presentation And Summary Of Significant Accounting Policies (Schedule Of Impact Of Restatement On Consolidated Statement Of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes	$ 13	$ 27,929
Income tax expense	6,490	10,277
Net income before earnings from equity-accounted investments	(6,477)	17,652
Net income	(5,104)	19,727
Net (loss) income attributable to Net1	$ (5,199)	$ 19,483
Net income per share, in United States dollars:
Basic earnings attributable to Net1 shareholders	$ (0.09)	$ 0.34
Diluted earnings attributable to Net1 shareholders	$ (0.09)	$ 0.34
As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes			$ 67,893
Income tax expense			41,353
Net income before earnings from equity-accounted investments			26,540
Net income			38,270
Net (loss) income attributable to Net1			$ 39,150
Net income per share, in United States dollars:
Basic earnings attributable to Net1 shareholders			$ 0.69
Diluted earnings attributable to Net1 shareholders			$ 0.69
Correction [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Change in fair value of equity securities			$ 32,473
Income before income taxes			32,473
Income tax expense			7,274
Net income before earnings from equity-accounted investments			25,199
Net income			25,199
Net (loss) income attributable to Net1			$ 25,199
Net income per share, in United States dollars:
Basic earnings attributable to Net1 shareholders			$ 0.44
Diluted earnings attributable to Net1 shareholders			$ 0.44
As Restated [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Change in fair value of equity securities			$ 32,473
Income before income taxes			100,366
Income tax expense			48,627
Net income before earnings from equity-accounted investments			51,739
Net income			63,469
Net (loss) income attributable to Net1			$ 64,349
Net income per share, in United States dollars:
Basic earnings attributable to Net1 shareholders			$ 1.13
Diluted earnings attributable to Net1 shareholders			$ 1.13