Income taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Dec. 31, 2017	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 225,000	$ (62,000)
Transition tax on previously unremitted foreign earnings		287,000
Unrecognized tax benefits		156,978
Amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate		102,871
Accrued interest related to the gross unrecognized tax benefits excluded from the unrecognized tax benefits		19,076
Decrease in unrecognized tax benefits that is reasonably possible (up to)		$ 120,000