Mortgage Banking Activities, Components of Loans Held For Sale (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Components of Residential Mortgages Held For Sale Gross, Fair Value	$ 293,762	$ 188,125
Mortgage Banking Revenue [Abstract]
Total originating and marketing revenue	129,117	51,982	49,438
Servicing revenue	40,185	39,661	38,162
Mortgage banking revenue	169,302	91,643	87,600
Residential Mortgage Loans Held For Sale Gross [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Number of days for past due for loan to be considered nonperforming (in days)	90 days	90 days
Residential mortgage loans held for sale, nonperforming	0	0
Credit losses recognized on residential mortgage loans held for sale	0	0
Residential Mortgage Loans Held For Sale Unpaid Principal Balance, Gross	269,718	177,319
Components of Residential Mortgages Held For Sale Gross, Fair Value	281,935	184,816
Mortgage Banking Revenue [Abstract]
Total originating and marketing revenue	120,599	57,418	45,243
Residential Mortgage Loan Commitments [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days outstanding for residential mortgage commitments, minimum (in days)	60 days	60 days
General number of days outstanding for residential mortgage commitments, maximum (in days)	90 days	90 days
Residential Mortgage Derivatives Notional Amount	356,634	189,770
Components of Residential Mortgages Held For Sale Gross, Fair Value	12,733	6,597
Mortgage Banking Revenue [Abstract]
Total originating and marketing revenue	6,136	4,345	1,755
Forward Sales Contracts[Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days for delivery of loans, for which the price is set by forward sales contracts, minimum (in days)	60 days	60 days
General number of days for delivery of loans, for which the price is set by forward sales contracts, maximum (in days)	90 days	90 days
Residential Mortgage Derivatives Notional Amount	598,442	349,447
Components of Residential Mortgages Held For Sale Gross, Fair Value	(906)	(3,288)
Mortgage Banking Revenue [Abstract]
Total originating and marketing revenue	$ 2,382	$ (9,781)	$ 2,440

Credit losses recognized on residential mortgage loans held for sale

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Maximum number of days for delivery of forward sales contracts.

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Maximum number of days outstanding for residential mortgage commitments to purchase.

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Minimum number of days for delivery of forward sales contracts.

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Minimum number of days outstanding for residential mortgage commitments to purchase.

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Noninterest income derived from the sale and changes in fair value of residential mortgage loans held for sale and fees for servicing of residential mortgage loans held by third parties. Also includes changes in the fair value of residential mortgage loan commitments and forward sales commitments considered to be derivative instruments.

+ References

No definition available.

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- Definition

Number of days past due for residential mortgage loans

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Total gain (loss) on mortgage loans held for sale, including mortgage loan commitments and forward sales contracts.

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Residential mortgage loans held for sale, 90 days past due or impaired.

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Unpaid principal balance of loans held for sale.

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Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Carrying amount of mortgage loans to individuals not classified as held for investment but are held-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6490309&loc=d3e48678-111004

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-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 1, 34

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-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

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Income from servicing real estate mortgages, credit cards, and other financial assets held by others. Also include any premiums received in lieu of regular servicing fees on such loans only as earned over the life of the loans. May also be net of any related impairment of fair value of capitalized service costs.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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-Article 9

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