Income Taxes (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Mar. 31, 2018	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Apr. 30, 2018
Income Taxes [Line Items]
Additional income tax benefits as an increase to earnings					$ 17,078	$ 20,100	$ 25,020
Income taxes payable	$ 160,427				160,427	29,150
Income tax expense (benefit)					205,724	76,459	87,157
Additional income tax expense from transition tax imposed on accumulated foreign earnings					$ 68,858	$ 65,612	$ 58,023
U.S. Federal income tax rate					28.00%	35.00%	35.00%
Increase to net earnings from tax holidays and tax incentives program					$ 33,500	$ 19,500
Increase to net earnings per diluted share from tax holidays and tax incentives program					$ 0.23	$ 0.14
Additional tax expense					$ 126,753
Additional tax expense payable over					8 years
Undistributed earnings	2,600,000				$ 2,600,000
Amount of deferred taxes that would have been recognized if the earnings has not been permanently reinvested	$ 4,000				$ 4,000
Tax Year 2018 [Member] | Scenario, Plan [Member]
Income Taxes [Line Items]
Income tax expense (benefit)				$ 138,000
Additional income tax expense from transition tax imposed on accumulated foreign earnings			$ 126,900
Additional income tax expense from adjustment of deferred tax assets				11,100
Australian Taxation Office [Member]
Income Taxes [Line Items]
Percentage of penalties on additional income tax	50.00%
Additional tax liabilities related to assessments	$ 75,900	$ 151,700
Interest related to assessments		$ 38,400	$ 38,400	$ 38,400
Income taxes payable								$ 75,900
Australian Taxation Office [Member] | Minimum [Member]
Income Taxes [Line Items]
Tax year under audit					2009
Australian Taxation Office [Member] | Maximum [Member]
Income Taxes [Line Items]
Tax year under audit					2013
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards	61,000				$ 61,000
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards	93,700				93,700
Valuation Allowance | Foreign Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards	9,200				9,200
Capital loss	$ 3,000				$ 3,000