Commitments And Contingencies Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Consumer Loan [Member]
Other Commitments [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	$ 44.2
Purchase commitment	100.0
Purchases made in connection with purchase commitments	$ 54.2
Debt and equity investments in mortgage originators [Member]
Other Commitments [Line Items]
Number of Investments	4
Mortgage Originator [Member]
Other Commitments [Line Items]
Commitments - Debt or Equity Investment	$ 2.0
Mortgage Originator [Member] | Due on or before June 12, 2016 [Member]
Other Commitments [Line Items]
Commitments - Debt or Equity Investment	2.0
Non-Exchange Traded Equity Investment in Mortgage Originator
Other Commitments [Line Items]
Guaranty Liabilities	7.5
Flow agreement March 2015 with mortgage originator [Member]
Other Commitments [Line Items]
Purchase commitment	200.0
Purchases made in connection with purchase commitments	9.4
Mortgage Loan Purchase Commitments [Member] | Flow agreement March 2015 with mortgage originator [Member]
Other Commitments [Line Items]
Derivative Asset, Notional Amount	7.7
Performance Guarantee [Member]
Other Commitments [Line Items]
Participation Interest in Repo Facility	10.0
Amount of Utilization	$ 156.2
Additional amount to be posted	5.00%
Financing Duration	6 months
Maximum Borrowings under Repo Facility	$ 200.0
Percentage of Repo Facility Allowed to Comprise of High Quality Jumbo Loans	7.50%