Derivatives And Risk Management (Narrative) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Secured Debt	$ 1,451,700,000	$ 1,376,700,000
Cash deposited as collateral	7,400,000	26,100,000
Derivative, Fair Value, Amount Offset Against Collateral, Net	13,665,000	8,732,000
Liability position at aggregate fair value	4,300,000	13,300,000
Collateral agreements	5,900,000	12,600,000
Commodity Contracts [Member]
Derivative [Line Items]
Letters of credit outstanding	38,500,000	20,300,000
Interest Rate Swap [Member]
Derivative [Line Items]
Cash deposited as collateral	$ 12,700,000