Debt - Summary of Interest Expense on All Convertible Debt (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Debt
Total interest expense recognized	$ 3,744	$ 3,861	$ 10,764	$ 11,292
3.50% Convertible Notes, 3.50% Series A Convertible Notes and 3.75% Convertible Notes
Debt
Interest expense related to contractual interest coupon	2,489	2,608	7,119	7,444
Interest expense related to amortization of debt discount	863	862	2,488	2,589
Interest expense related to amortization of debt issuance costs	$ 392	$ 391	$ 1,157	$ 1,259