Organization and Summary of Significant Accounting Policies Risks - Concentration Revenue, Accounts Receivable and Dependence on Suppliers (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 customer	Dec. 31, 2011 customer	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
customers with 10% revenue concentration	0	0
customers with 10 % accts rec concentration	0	0
Concentration Risk, Percentage	7.50%	2.00%	2.60%
Purchases from significant supplier	$ 23.8	$ 21.1	$ 19.1
Lease Agreements [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	60.9	46.9	51.4
Lease Transfers In Ending Accounts Receivable	$ 0.7	$ 0.2