Derivatives (Narrative) (Details) (Fixed price swap contracts, USD $)	Mar. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Fixed price swap contract (in gallons)	6,400,000
Prepaid Expenses and Other Assets
Derivative [Line Items]
Derivative asset (Less than $1 as of March 31, 2014 and December 31, 2013)	$ 1,000,000	$ 1,000,000
Accrued Expenses and Other Liabilities
Derivative [Line Items]
Derivative liability (Less than $1 as of March 31, 2014 and December 31, 2013)	1,000,000	1,000,000
Accumulated Other Comprehensive Income (Loss)
Derivative [Line Items]
Derivative accumulated other comprehensive income (Less than $1 as of March 31, 2014 and December 31, 2013)	$ 1,000,000	$ 1,000,000