Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Accruing TDRs	$ 60,296	$ 60,558
Non-accrual TDRs	27,277	31,035
Total TDRs	87,573	91,593
Real-estate - residential mortgage [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	27,565	28,511
Real-estate commercial mortage [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	17,427	17,563
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	5,522	5,833
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	3,092	3,942
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	6,530	4,556
Commercial - unsecured [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	128	120
Consumer Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	12	14
Consumer - direct [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	$ 20	$ 19