Commitments and Contingencies (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Guarantor Obligations [Line Items]
Aggregate exposure outstanding	$ 80,800,000
Total gross claim liability recorded	$ 0
Financial Guarantee Insurance Contracts Outstanding Weighted Average Contract Period	25 years	25 years 2 months 12 days
Financial Guarantee Related to Securities Including Some Issued By European Financials [Member]
Guarantor Obligations [Line Items]
Closing number of financial guarantee contracts	2