Derivative Financial Instruments - Fair Value of Derivative Instruments on the Consolidated Balance Sheets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Jun. 30, 2014
Short-term derivative assets: [Member] | Derivative Instruments Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 1,139		$ 5,474
Short-term derivative assets: [Member] | Derivative Instruments Not Designated as Accounting Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Long-term derivative assets: [Member] | Derivative Instruments Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	862	[1]
Long-term derivative assets: [Member] | Derivative Instruments Not Designated as Accounting Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	0	[1]
Short-term derivative liabilities: [Member] | Derivative Instruments Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	3,930		252
Short-term derivative liabilities: [Member] | Derivative Instruments Not Designated as Accounting Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	929		69
Long-term derivative liabilities: [Member] | Derivative Instruments Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0		0
Long-term derivative liabilities: [Member] | Derivative Instruments Not Designated as Accounting Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 0		$ 0

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