Loans And Allowance For Loan Losses Troubled Debt Restructurings by Type of Modification (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 100,869	$ 110,608
TDR Non-market interest rates [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	77,922	88,588
TDR Assistance programs [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6,671	6,685
TDR-Bankruptcy non-affirmation [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8,386	7,283
TDR Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	271	256
TDR Non-accrual loans [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 7,619	$ 7,796