Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 58,977	$ 60,558
Non-accrual TDRs (1)	27,904	31,035
Total TDRs	86,881	91,593
Real-estate - residential mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	26,854	28,511
Real-estate commercial mortage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	16,085	17,563
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	7,422	5,833
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	843	3,942
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	7,668	4,556
Commercial - unsecured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	66	120
Consumer Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	20	14
Consumer - direct [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 19	$ 19