Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 61,476	$ 61,341	$ 60,145
Mortgage Servicing Rights (MSR) Impairment (Recovery)	(200)	(425)	$ 321
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Commercial loans held for sale	12,474
Provision for credit losses	(559)
Mortgage loans held for sale	108,010	124,915
market valuation adjustment, loans held for sale	(3,760)	(155)
Other real estate owned	9,752	10,988
Foreclosure / OREO expense, net	(1,091)	(2,653)
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Impaired loans	79,270	41,891
Provision for Credit Losses, Impaired Loans	(75,194)	(7,796)
Mortgage servicing rights	73,149	70,686
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ 200	$ 425