Quantitative Information About Level 3 Fair Value Measurements - Prepayment Assumptions (Details) ([RetainedInterestMember])	12 Months Ended
Dec. 31, 2012
Prepayment Assumption [Line Items]
Prepayment Method	Constant Prepayment Rate
[MaximumMember]
Prepayment Assumption [Line Items]
Prepayment Range	10.00%
[MinimumMember]
Prepayment Assumption [Line Items]
Prepayment Range	10.00%
[WeightedAverageMember]
Prepayment Assumption [Line Items]
Prepayment Range	10.00%

Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Name:	us-gaap_FairValueInputsPrepaymentRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration