Income Taxes (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Federal operating-loss carryforwards		$ 41,500,000
Deferred tax assets tax losses total		39,300,000
Deferred Tax Assets, Tax Credit Carryforwards		10,019,000	9,138,000
Combined future tax benefits		49,300,000
Valuation allowance		(25,358,000)	(19,120,000)
Alternative fuel tax credit	3,300,000
Cumulative undistributed earnings		29,900,000
Income tax receivables		10,600,000	6,600,000
Gross unrecognized tax benefits		11,900,000	15,000,000
Accrued interest and penalties		3,500,000	5,300,000
Unrecognized tax benefits that, if recognized, would change the effective tax rate		6,500,000	8,200,000
Interest and penalties		1,800,000	1,300,000
Unrecognized tax benefits decrease		$ 1,800,000