Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 58,910	$ 61,605
Non-accrual TDRs (1)	23,553	28,659
Total TDRs	82,463	90,264
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	21,762	24,102
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	16,444	15,685
Real-estate - home equity
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	15,505	16,665
Commercial
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	5,192	5,143
Consumer
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 7	$ 10