Condensed Financial Information Of Parent Company Parent Company Information (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Other assets	$ 522,896	$ 540,723
Total assets	25,731,354	24,994,876
Subordinated debentures	453,846	462,437
Total liabilities	20,905,766	20,017,278
Stockholders' Equity Attributable to Parent Only	4,825,588	4,977,598	$ 4,479,055	$ 4,397,691
Total liabilities and stockholders' equity	25,731,354	24,994,876
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	244,859	185,511
Investments In Consolidated Banking Subsidiaries	4,641,649	4,869,391
Other assets	79,516	76,458
Total assets	4,966,024	5,131,360
Subordinated debentures	135,055	147,233
Other Liabilities	5,381	6,529
Total liabilities	140,436	153,762
Stockholders' Equity Attributable to Parent Only	4,825,588	4,977,598
Total liabilities and stockholders' equity	$ 4,966,024	$ 5,131,360