Fair Value Measurements - Summary of Carrying Value and Estimated Fair Value of all Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Non-recurring basis | Carrying Value
Fair value measurement
Long term debt	$ 131,077	$ 164,571
Non-recurring basis | Carrying Value | Level 2 | 3.75% Convertible Notes
Fair value measurement
Long term debt	69,382
Non-recurring basis | Carrying Value | Level 2 | 3.50% Convertible Notes
Fair value measurement
Long term debt		44,099
Non-recurring basis | Carrying Value | Level 2 | 3.50% Series A Convertible Notes
Fair value measurement
Long term debt		68,924
Non-recurring basis | Fair Value
Fair value measurement
Long term debt	132,437	174,676
Non-recurring basis | Fair Value | Level 2 | 3.75% Convertible Notes
Fair value measurement
Long term debt	70,742
Non-recurring basis | Fair Value | Level 2 | 3.50% Convertible Notes
Fair value measurement
Long term debt		48,146
Non-recurring basis | Fair Value | Level 2 | 3.50% Series A Convertible Notes
Fair value measurement
Long term debt		74,982
Secured Debt | Carrying Value
Fair value measurement
Long term debt	38,010
Secured Debt | Fair Value
Fair value measurement
Long term debt	38,010
Revolving Credit Facility | Carrying Value
Fair value measurement
Long term debt	23,685	51,548
Revolving Credit Facility | Fair Value
Fair value measurement
Long term debt	$ 23,685	$ 51,548