Loans and Allowance for Credit Losses Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 59,560	$ 60,558
Non-accrual TDRs	27,850	31,035
Total TDRs	87,410	91,593
Residential Mortgage
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	27,617	28,511
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	15,957	17,563
Construction - commercial residential
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	726	3,942
Commercial - secured
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	6,564	5,833
Real estate – home equity
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	8,594	4,556
Commercial - unsecured
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	63	120
Consumer - direct
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	20	19
Consumer - indirect:
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 19	$ 14