Derivative Instruments - Fair Value of Derivative Instruments on the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018
Designated as Cash Flow Hedges | Short-term Investments | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 10	$ 0
Designated as Cash Flow Hedges | Long-term Derivative Assets | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	12	0
Designated as Cash Flow Hedges | Short-Term Derivative Liabilities | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	6,527	3,081
Designated as Cash Flow Hedges | Other Long Term Liabilities | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	553	386
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	0	0
Not Designated as Hedging Instrument | Short-term Investments
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	44	0
Not Designated as Hedging Instrument | Long-term Derivative Assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	0	0
Not Designated as Hedging Instrument | Short-Term Derivative Liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ 771	$ 219