Loans and Allowance for Credit Losses Loans Modified Under Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 61,211	$ 61,605
Non-accrual TDRs (1)	29,958	28,659
Total TDRs	91,169	90,264
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	22,389	24,102
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	16,680	15,685
Real-estate - home equity
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	16,389	16,665
Commercial
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	5,744	5,143
Consumer
Financing Receivable, Modifications [Line Items]
Total Accruing Troubled Debt Restructurings	$ 9	$ 10