Condensed Financial Information Of Parent Company Parent Company Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Cash	$ 398,437	$ 419,670
Other assets	540,723	319,779
Total assets	24,994,876	21,869,767
Subordinated debentures	462,437	440,744
Total liabilities	20,017,278	17,390,712
Stockholders' Equity Attributable to Parent Only	4,977,598	4,479,055	$ 4,397,691	$ 3,506,230
Total liabilities and stockholders' equity	24,994,876	21,869,767
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	185,511	494,765
Investments In Consolidated Banking Subsidiaries	4,869,391	4,053,711
Other assets	76,458	67,074
Total assets	5,131,360	4,615,550
Subordinated debentures	147,233	134,360
Other Liabilities	6,529	2,135
Total liabilities	153,762	136,495
Stockholders' Equity Attributable to Parent Only	4,977,598	4,479,055
Total liabilities and stockholders' equity	$ 5,131,360	$ 4,615,550