Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period Of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, Adjusted Balance	Performance/Service Based RSAs, RSA,	Board Authorized Purchase Program [Member]	Series C Preferred Stock	Series D Preferred Stock	Series E Preferred Stock	Series F Preferred Stock	Preferred Equity	Preferred Equity Cumulative Effect, Period Of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period Of Adoption, Adjusted Balance	Surplus	Surplus Cumulative Effect, Period Of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period Of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period Of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period Of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period Of Adoption, Adjusted Balance	Treasury Stock Performance/Service Based RSAs, RSA,	Treasury Stock Board Authorized Purchase Program [Member]
Beginning balance at Dec. 31, 2020	$ 4,090,933									$ 353,512		$ 1,752		$ 1,720,329		$ 2,458,920			$ 12,618		$ (456,198)
Comprehensive income (loss)
Net income	94,301															94,301
Other comprehensive (loss)	(16,811)																		(16,811)
Comprehensive income (loss)	77,490
Common stock issued
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	10,556													(16,986)		0					27,542
Purchase of treasury stock,				$ (3,593)	$ (17,973)																		$ (3,593)	$ (17,973)
Cash dividends
Common stock	(27,870)															(27,870)
Preferred stock(b)	(5,207)															(5,207)
Stock-based compensation expense, net	3,444													3,444
Ending balance at Mar. 31, 2021	4,127,780									353,512		1,752		1,706,786		2,520,144			(4,193)		(450,222)
Cash dividends
Preferred Stock, Dividends, Per Share, Cash Paid						$ 0.3828125	$ 0.3359375	$ 0.3671875	$ 0.3515625
Beginning balance at Dec. 31, 2021	4,024,853		$ 4,026,566							193,195	$ 193,195	1,752	$ 1,752	1,713,851	$ 1,713,851	2,672,601		$ 2,674,314	(10,317)	$ (10,317)	(546,229)	$ (546,229)
Beginning balance (Accounting Standards Update 2016-13) at Dec. 31, 2021		$ 1,713															$ 1,713
Comprehensive income (loss)
Net income	74,262															74,262
Other comprehensive (loss)	(126,708)																		(126,708)
Comprehensive income (loss)	(52,445)
Common stock issued
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	6,654													(11,911)							18,565
Purchase of treasury stock,				$ (5,193)																			$ (5,193)
Cash dividends
Common stock	(30,583)															(30,583)
Preferred stock(b)	(2,875)															(2,875)
Stock-based compensation expense, net	6,164													6,164
Ending balance at Mar. 31, 2022	$ 3,948,287									$ 193,195		$ 1,752		$ 1,708,104		$ 2,715,118			$ (137,024)		$ (532,858)