Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013 subsidiary	Mar. 31, 2012
Schedule of Summary of Significant Accounting Policies [Line Items]
Number of Subsidiaries	2
Guarantee and commitment fees	$ 6,612	$ 5,930
FMMSC
Schedule of Summary of Significant Accounting Policies [Line Items]
Guarantee and commitment fees	$ 2,600	$ 2,600

This item represents the portion of monthly guaranty fees collected representing the interest imputed and recognized under the prospective interest method on the present value of the contractually stipulated guarantee payments at inception of the contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13 (d))

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 99-20

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_GuarantyFeeIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration