Condensed Financial Information - Parent Company Only Income statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Total Non-Interest Income	$ 229,388	$ 216,160	$ 195,525
Income Before Income Taxes	202,235	263,988	232,970
Income tax benefit	24,194	37,649	24,577
Net Income	178,040	226,339	208,393
Preferred stock dividends	(2,135)	0	0
Net Income Available to Common Shareholders	175,905	226,339	208,393
Parent
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries	161,000	209,000	150,000
Other (1)	100	191,978	188,165
Total Non-Interest Income	161,100	400,978	338,165
Expenses	48,634	218,837	210,333
Income Before Income Taxes	112,466	182,141	127,832
Income tax benefit	(9,679)	(5,798)	(7,100)
Income before equity in undistributed income of subsidiaries	122,145	187,939	134,932
Net Income	178,040	226,339	208,393
Parent | Bank subsidiary
Condensed Financial Statements, Captions [Line Items]
Non-bank subsidiaries	162,037	44,926	74,631
Parent | Non-bank subsidiaries
Condensed Financial Statements, Captions [Line Items]
Non-bank subsidiaries	$ (106,142)	$ (6,526)	$ (1,170)