Goodwill and intangible assets - Additional information (Details) $ in Thousands	6 Months Ended
	Dec. 31, 2018 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 105,090
Estimated amortization expense, year ending June 30, 2019	196,130
Estimated amortization expense, year ending June 30, 2020	185,468
Estimated amortization expense, year ending June 30, 2021	180,870
Estimated amortization expense, year ending June 30, 2022	175,010
Estimated amortization expense, year ending June 30, 2023	$ 167,513