Basis of Presentation and Accounting Policies (Narrative) (Details) $ in Thousands			3 Months Ended
		Jan. 01, 2020 USD ($)	Mar. 31, 2020 branch ATM	Dec. 31, 2019 USD ($)
Accounting Policies [Abstract]
Number of branches | branch			299
Number of ATMs | ATM			386
Basis Of Presentation [Line Items]
Period of forecast reverts for loans			1 year
ASU 2016-13
Basis Of Presentation [Line Items]
Adjustment from adoption of ASU	[1]			$ (35,721)
ASU 2016-13 | Unfunded Loan Commitment
Basis Of Presentation [Line Items]
Adjustment from adoption of ASU		$ 35,700
Cost basis of loans		$ 62,200

[1] For additional information, see "Part I - Item 1. Financial Statements and Supplementary Data - Note 1 - Basis of Presentation" in this Report.