Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 59,622	$ 59,560
Non-accrual TDRs (1)	27,220	27,850
Total TDRs	86,842	87,410
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	27,033	27,617
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	15,237	15,957
Real-estate - home equity
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	9,601	8,594
Commercial - secured
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	7,441	6,627
Construction - commercial residential
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	273	726
Consumer - direct
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 37	$ 39