Condensed Financial Information Of Parent Company Condensed Financial Information Of Parent Company (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Other assets	$ 860,326	$ 636,811
Total assets	29,498,442	26,770,806
Subordinated debentures	465,800
Total liabilities	25,903,491	21,816,109
Stockholders' Equity Attributable to Parent Only	3,594,951	4,954,697	$ 4,825,588	$ 4,977,598
Total liabilities and stockholders' equity	29,498,442	26,770,806
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	127,849	113,961
Investments In Consolidated Banking Subsidiaries	3,530,823	4,905,033
Other assets	75,835	74,479
Total assets	3,734,507	5,093,473
Subordinated debentures	135,055	135,055
Other Liabilities	4,501	3,721
Total liabilities	139,556	138,776
Stockholders' Equity Attributable to Parent Only	3,594,951	4,954,697
Total liabilities and stockholders' equity	$ 3,734,507	$ 5,093,473