Significant Accounting Policies - Recent accounting pronouncements (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	$ (10,762,841)	$ (9,188,962)	$ (8,823,384)
Selling, general and administrative expenses	(1,657,152)	(1,453,935)	$ (1,359,360)
Retained earnings (accumulated deficit)	11,625,975	10,930,348
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	25,000	70,000
Selling, general and administrative expenses	17,000	$ 41,000
Accounting Standard Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings (accumulated deficit)	$ (18,000)