Derivative Financial Instruments - Fair Value of Derivative Instruments on the Consolidated Balance Sheets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Jun. 30, 2013
Short-term derivative assets: | Derivatives Designated as Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 15,434		$ 0
Short-term derivative assets: | Derivatives Not Designated as Accounting Hedges
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3,100		4
Long-term derivative assets: | Derivatives Designated as Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,233	[1]	0	[1]
Long-term derivative assets: | Derivatives Not Designated as Accounting Hedges
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	0	[1]
Short-term derivative liabilities: | Derivatives Designated as Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		9,331
Short-term derivative liabilities: | Derivatives Not Designated as Accounting Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		565
Other current liabilities: | Derivatives Designated as Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		0
Other current liabilities: | Derivatives Not Designated as Accounting Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		25
Long-term derivative liabilities: | Derivatives Designated as Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		1,129
Long-term derivative liabilities: | Derivatives Not Designated as Accounting Hedges
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 0		$ 0

[1] Included in "Other assets" on the consolidated balance sheets.