8. Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total interest expense	$ 79,941	$ 57,745	$ 50,395
Securitization Trust Debt [Member]
Total interest expense	69,178	48,631	38,558
Warehouse lines of credit [Member]
Total interest expense	8,569	6,127	5,217
Senior Secured Debt Related Party [Member]
Total interest expense	0	0	1,651
Debt Secured by Receivables, Fair Value [Member]
Total interest expense	0	0	772
Residual interest financing [Member]
Total interest expense	846	1,405	1,989
Subordinated renewable notes [Member]
Total interest expense	$ 1,348	$ 1,582	$ 2,208