Mortgage Banking Activities, Components of Loans Held For Sale (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Components of Residential Mortgage Loans Held for Sale [Abstract]
Fair Value	$ 357,414	$ 373,253	$ 304,182
Residential mortgage loans held for sale [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	90 days
Residential mortgage loans held for sale, nonperforming	$ 0	$ 0	$ 0
Credit losses recognized on residential mortgage loans held for sale	0	0
Components of Residential Mortgage Loans Held for Sale [Abstract]
Unpaid Principal Balance	336,974	360,126	291,537
Fair Value	$ 348,400	$ 366,183	$ 298,212
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	60 days
General number of days outstanding for residential mortgage commitments, maximum (in days)	90 days	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 742,742	$ 638,925	$ 627,505
Fair Value	$ 18,161	$ 8,480	$ 9,971
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	60 days
General number of days for delivery for loans, for which the price is set by forward sales contracts, maximum (in days)	90 days	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 1,073,343	$ 790,131	$ 701,066
Fair Value	$ (9,147)	$ (1,410)	$ (4,001)