6. Interest Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Components of interest income
Interest on Finance Receivables	$ 55,796	$ 41,076	$ 106,954	$ 81,221
Residual interest income		234		458
Other interest income	1	236	10	478
Interest income	$ 55,797	$ 41,546	$ 106,964	$ 82,157