Mortgage Servicing Rights - Significant Econcomic Assumptions (Details)	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Fixed [Member]
Assumption for Fair Value of MSRs
Weighted-average OAS	4.08%	4.00%
Weighted-average life, in years	5 years 2 months 8 days	3 years 7 months 25 days
Adjustable [Member]
Assumption for Fair Value of MSRs
Weighted-average OAS	7.33%	6.63%
Weighted-average life, in years	2 years 9 months	2 years 1 month 6 days

Weighted average life of securitized assets regardless of when the transfer occurred, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration