Debt - Summary of Interest Expense on All Convertible Debt (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Debt
Total interest expense recognized	$ 3,503	$ 3,712	$ 7,020	$ 7,431
3.50% Convertible Notes, 3.50% Series A Convertible Notes and 3.75% Convertible Notes
Debt
Interest expense related to contractual interest coupon	2,305	2,427	4,630	4,836
Interest expense related to amortization of debt discount	815	865	1,625	1,727
Interest expense related to amortization of debt issuance costs	$ 383	$ 420	$ 765	$ 868