Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Entity Information [Line Items]
Concentration Risk, Percentage	48.20%	49.00%	51.00%
Interest Costs Incurred, Capitalized	$ 0.1	$ 0	$ 0.1
Amortization of Financing Costs and Discounts	2.6	3.1	3.0
Unrealized gain (losses) on securities, net of reversals	(6.3)	(4.9)	11.8
Deferred Income Tax Expense (Benefit)	(28.3)	(8.7)	(18.4)
Notes payable	7.9	0
Gains (Losses) on Extinguishment of Debt	0	0	(20.7)
Maximum [Member]
Entity Information [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Percentage Used To Determine Noncontrolling Interest Presentation	1.00
Minimum [Member]
Entity Information [Line Items]
Equity Method Investment, Ownership Percentage	20.00%
Percentage Used To Determine Noncontrolling Interest Presentation	0.50
Home Depot [Member]
Entity Information [Line Items]
Concentration Risk, Percentage		10.90%	10.90%
Taiga [Member]
Entity Information [Line Items]
Concentration Risk, Percentage			10.10%
Deferred Loss on Early Extinguishment of Debt [Member]
Entity Information [Line Items]
Gains (Losses) on Extinguishment of Debt			3.8
Non Recourse Notes Payable 2018 [Member]
Entity Information [Line Items]
Notes payable	368.7	368.7
Swap [Member]
Entity Information [Line Items]
Unrealized gain (losses) on securities, net of reversals	(1.4)	(0.7)
Deferred Income Tax Expense (Benefit)	$ (0.3)