Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 452,390	$ 452,390	$ 452,390	$ 497,267	$ 497,267	$ 497,267
Community Banking Reporting Unit
Goodwill [Line Items]
Goodwill	256,323		256,323
Wholesale Banking Reporting Unit
Goodwill [Line Items]
Goodwill	171,636		171,636
Consumer Mortgage Reporting Unit
Goodwill [Line Items]
Goodwill	0		0
Wealth Management Reporting Unit
Goodwill [Line Items]
Goodwill	$ 24,431		$ 24,431