Accounting Policies - Allowance for Losses (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012 contract	Sep. 30, 2012 contract
Financing Receivable, Modifications [Line Items]
Loans receivable allowance calculation period		3 years
Impaired loans receivable past due period minimum		90 days
Financing Loans
Financing Receivable, Modifications [Line Items]
Before restructuring investment recorded during the period	$ 400,000	$ 1,500,000
After restructuring investment recorded during the period	400,000	1,700,000
Number of defaulted contracts	1	1
Defaulted contract recorded investment	100,000	100,000
Impaired troubled debt restructuring allowance write-down	$ 46,000	$ 200,000