Related Parties (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Gold Hill 08 Funds
Related Party Transaction [Line Items]
Line of credit facility, maximum borrowing capacity	$ 85
Gold Hill 08 Funds
Related Party Transaction [Line Items]
Loan amount outstanding to related party during period, maximum	38
Line of credit facility amount syndicated to another lender	27
Interest rate associated with related party loan facility	national Prime plus one percent
Revolving line of credit facility, outstanding amount	$ 38	$ 31
Gold Hill Capital 2008, LLC
Related Party Transaction [Line Items]
SVBFG Ownership of each Fund	83.80%