Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended	9 Months Ended	15 Months Ended	12 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014	Dec. 31, 2009 Alternative Fuel Mixture Credit [Member]	Dec. 31, 2009 Cellulosic Biofuel Producer Credit [Member]	Mar. 31, 2013 Exchange of Alternative Fuel Tax Benefit [Member]
Effective Tax Reconciliation [Line Items]
Income tax expense at federal statutory rate	$ 38,000,000	$ 25,000,000
U.S. federal statutory income tax rate	35.00%	35.00%
Tax Credit Amount per Gallon						0.50	1.01
Payment to exchange AFMC for CBPC	70,311,000	0
Gallons Exchanged	120000000
Income Tax Benefit								19,000,000
Deferred Other Tax Expense (Benefit)			(29,000,000)	(60,000,000)	(89,000,000)
REIT Income Not Subject to Tax	(11,000,000)	(5,000,000)
REIT Income Not Subject to Tax (Rate)	(10.10%)	(7.70%)
Other Reconciling Items	(2,000,000)	(1,000,000)
Other Reconciling Items (Rate)	(1.50%)	(0.80%)
Effective IncomeTax Continuing Operations Before Discrete Items	25,000,000	19,000,000
Effective Income Tax Rate Continuing Operations Before Discrete Items	23.40%	26.50%
Tax Credits CBPC for AFMC Exchange	(19,000,000)	0
Tax Credits CBPC for AFMC Exchange (Rate)	(17.50%)	0.00%
Other Adjustments	(2,000,000)	(1,000,000)
Other Adjustments (Rate)	(1.80%)	(0.70%)
Income Tax Expense as reported	4,445,000	18,303,000
Effective tax rate	4.10%	25.80%
Proceeds from Divestiture of Businesses	$80 million plus a working capital adjustment
Discontinued Operation, Tax Effect of Discontinued Operation	22,273,000	422,000
Discontinued Operation, Tax Effect of Income (Loss) from Disposal of Discontinued Operation	$ 21,400,000