Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 61,165	$ 60,558
Non-accrual TDRs (1)	24,887	31,035
Total TDRs	86,052	91,593
Real-estate - residential mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	27,324	28,511
Real-estate commercial mortage [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	17,808	17,563
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	5,645	5,833
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	3,086	3,942
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	7,173	4,556
Commercial - unsecured [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	111	120
Consumer Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	0	14
Consumer - direct [Member]
Financing Receivable, Modifications [Line Items]
Total accruing TDRs	$ 18	$ 19