Fair Value Measurements and Disclosures Concentration of Risk (Details) $ in Thousands	Jun. 30, 2016 USD ($)
Concentration Risk [Line Items]
Fair Value of Derivative Assets	$ 111,584
JPMorgan Chase Bank [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	29,011	[1]
Canadian Imperial Bank of Commerce [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	33,559	[1]
Bank of Nova Scotia [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	22,676	[1]
Wells Fargo Bank [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	13,351	[1]
Natixis [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	10,418	[1]
Other Lenders in Our Credit Facility [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	2,329
Various [Member]
Concentration Risk [Line Items]
Fair Value of Derivative Assets	$ 240	[2]

[1] Major lender in our revolving credit facility. See Note 7, Long-Term Debt.

[2] Represents a total of six counterparties.