Mortgage Banking Activities, Components of Loans Held For Sale (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Components of Residential Mortgages Held For Sale Gross, Fair Value	$ 286,211	$ 247,039	$ 293,762
Number of days for past due loans (in days)	90 days
Mortgage and Marketing Revenue [Abstract]
Total originating and marketing revenue	29,910	23,081
Servicing revenue	10,066	9,997
Mortgage banking revenue	39,976	33,078
Residential Mortgage Loans Held For Sale Gross [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Residential Mortgage Loans Held For Sale Unpaid Principal Balance, Gross	264,608	230,241	269,718
Components of Residential Mortgages Held For Sale Gross, Fair Value	274,710	237,741	281,935
Number of days for past due loans (in days)	90 days	90 days	90 days
Residential mortgage loans held for sale, nonperforming	0	0	0
Credit losses recognized on residential mortgage loans held for sale	0	0
Mortgage and Marketing Revenue [Abstract]
Total originating and marketing revenue	30,235	17,092
Residential Mortgage Loan Commitments [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Residential Mortgage Derivatives Notional Amount	466,571	302,303	356,634
Components of Residential Mortgages Held For Sale Gross, Fair Value	13,343	8,907	12,733
Minimum Number of Days Outstanding For Residential Mortgage Commitments	60 days	60 days	60 days
Maximum Number of Days Outstanding For Residential Mortgage Commitments	90 days	90 days	90 days
Mortgage and Marketing Revenue [Abstract]
Total originating and marketing revenue	610	2,310
Forward Sales Contracts[Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Residential Mortgage Derivatives Notional Amount	712,144	520,165	598,442
Components of Residential Mortgages Held For Sale Gross, Fair Value	(1,842)	391	(906)
Minimum Number of Days for Delivery of Forward Sales Contracts	60 days	60 days	60 days
Maximum Number of Days for Delivery of Forward Sales Contracts	90 days	90 days	90 days
Mortgage and Marketing Revenue [Abstract]
Total originating and marketing revenue	$ (935)	$ 3,679