Mortgage Banking Activities, Components of Loans Held For Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Number of days for past due for a residential mortgage 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
Components of Residential Mortgage Loans Held for Sale [Abstract]
Unpaid principal balance	286,414	293,637
Residential mortgage loans held for sale, Fair value	286,971	299,505
Total residential mortgages loans held for sale and mortgage loan commitments, net of forward sales contracts	$ 301,897	$ 308,439
Not Designated as Hedging Instrument [Member] | 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
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 318,359	$ 601,147
Derivative, Net fair value	$ 9,733	$ 8,134
Not Designated as Hedging Instrument [Member] | 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
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 569,543	$ 884,710
Derivative, Net fair value	$ 5,193	$ 800