Mortgage Banking Activities, Components of Loans Held For Sale (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Components of Residential Mortgages Held For Sale Gross, Fair Value	$ 301,057	$ 259,174	$ 301,057	$ 259,174	$ 293,762
Number of days for past due loans (in days)	90 days		90 days
Mortgage and Marketing Revenue [Abstract]
Originating and marketing revenue	26,356	29,689	56,266	52,770
Servicing revenue	10,240	9,859	20,306	19,856
Mortgage banking revenue	36,596	39,548	76,572	72,626
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	284,454	236,160	284,454	236,160	269,718
Components of Residential Mortgages Held For Sale Gross, Fair Value	280,962	247,893	280,962	247,893	281,935
Number of days for past due loans (in days)	90 days	90 days	90 days	90 days	90 days
Residential mortgage loans held for sale, nonperforming	0	0	0	0	0
Credit losses recognized on residential mortgage loans held for sale	0	0
Mortgage and Marketing Revenue [Abstract]
Originating and marketing revenue	17,763	27,706	47,998	44,798
Residential Mortgage Loan Commitments [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Residential Mortgage Derivatives Notional Amount	547,508	392,247	547,508	392,247	356,634
Components of Residential Mortgages Held For Sale Gross, Fair Value	(1,709)	15,807	(1,709)	15,807	12,733
Minimum Number of Days Outstanding For Residential Mortgage Commitments	60 days	60 days	60 days	60 days	60 days
Maximum Number of Days Outstanding For Residential Mortgage Commitments	90 days	90 days	90 days	90 days	90 days
Mortgage and Marketing Revenue [Abstract]
Originating and marketing revenue	(15,052)	6,900	(14,442)	9,210
Forward Sales Contracts[Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Residential Mortgage Derivatives Notional Amount	740,752	605,856	740,752	605,856	598,442
Components of Residential Mortgages Held For Sale Gross, Fair Value	21,804	(4,526)	21,804	(4,526)	(906)
Minimum Number of Days for Delivery of Forward Sales Contracts	60 days	60 days	60 days	60 days	60 days
Maximum Number of Days for Delivery of Forward Sales Contracts	90 days	90 days	90 days	90 days	90 days
Mortgage and Marketing Revenue [Abstract]
Originating and marketing revenue	$ 23,645	$ (4,917)	$ 22,710	$ (1,238)