Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series C Preferred Stock	Series D Preferred Stock	Series E Preferred Stock	Series F Preferred Stock	Board Authorized Purchase Program [Member]	Performance/Service Based RSAs, RSA,	Cumulative Effect, Period Of Adoption, Adjustment	Preferred Equity	Preferred Equity Series C Preferred Stock	Common Stock	Surplus	Retained Earnings	Retained Earnings Series C Preferred Stock	Retained Earnings Cumulative Effect, Period Of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Treasury Stock Board Authorized Purchase Program [Member]	Treasury Stock Performance/Service Based RSAs, RSA,
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
Net other comprehensive (loss) during period	(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,						$ (17,973)	$ (3,593)											$ (17,973)	$ (3,593)
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, 2020	4,090,933								353,512		1,752	1,720,329	2,458,920			12,618	(456,198)
Comprehensive income (loss)
Net income	185,307												185,307
Net other comprehensive (loss) during period	(9,729)															(9,729)
Comprehensive income (loss)	175,578
Ending balance at Jun. 30, 2021	4,110,052								290,200		1,752	1,708,246	2,576,766			2,889	(469,801)
Beginning balance at Mar. 31, 2021	4,127,780								353,512		1,752	1,706,786	2,520,144			(4,193)	(450,222)
Comprehensive income (loss)
Net income	91,007												91,007
Net other comprehensive (loss) during period	7,082															7,082
Comprehensive income (loss)	98,088
Common stock issued
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	7,618											(3,632)	0				11,250
Purchase of treasury stock,						$ (29,972)	(856)											$ (29,972)	(856)
Cash dividends
Common stock	(27,822)												(27,822)
Preferred stock(b)	(4,875)												(4,875)
Stock-based compensation expense, net	5,092											5,092
Ending balance at Jun. 30, 2021	4,110,052								290,200		1,752	1,708,246	2,576,766			2,889	(469,801)
Cash dividends
Preferred Stock, Dividends, Per Share, Cash Paid		$ 0.3197115	$ 0.3359375	$ 0.3671875	$ 0.3515625
Stock Redeemed or Called During Period, Value		$ (65,000)								$ (63,313)				$ (1,687)
Beginning balance at Dec. 31, 2021	4,024,853								193,195		1,752	1,713,851	2,672,601			(10,317)	(546,229)
Beginning balance (Mortgage Servicing Rights, Accounting Policy Change From At Cost to Fair Value) at Dec. 31, 2021	4,026,566							$ 1,713	193,195		1,752	1,713,851	2,674,314		$ 1,713	(10,317)	(546,229)
Comprehensive income (loss)
Net income	74,262												74,262
Net other comprehensive (loss) during period	(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)
Beginning balance at Dec. 31, 2021	4,024,853								193,195		1,752	1,713,851	2,672,601			(10,317)	(546,229)
Beginning balance (Mortgage Servicing Rights, Accounting Policy Change From At Cost to Fair Value) at Dec. 31, 2021	4,026,566							$ 1,713	193,195		1,752	1,713,851	2,674,314		$ 1,713	(10,317)	(546,229)
Comprehensive income (loss)
Net income	161,086												161,086
Net other comprehensive (loss) during period	(172,472)															(172,472)
Comprehensive income (loss)	(11,386)
Ending balance at Jun. 30, 2022	3,959,382								193,195		1,752	1,710,319	2,768,736			(182,788)	(531,832)
Beginning balance at Mar. 31, 2022	3,948,287								193,195		1,752	1,708,104	2,715,118			(137,024)	(532,858)
Comprehensive income (loss)
Net income	86,824												86,824
Net other comprehensive (loss) during period	(45,764)															(45,764)
Comprehensive income (loss)	41,060
Common stock issued
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	139											(1,771)					1,910
Purchase of treasury stock,							$ (884)												$ (884)
Cash dividends
Common stock	(30,331)												(30,331)
Preferred stock(b)	(2,875)												(2,875)
Stock-based compensation expense, net	3,986											3,986
Ending balance at Jun. 30, 2022	$ 3,959,382								$ 193,195		$ 1,752	$ 1,710,319	$ 2,768,736			$ (182,788)	$ (531,832)