Condensed Financial Statements of Parent Company (Schedule of Condensed Statements of Cash Flows) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Net income	$ 597,973	$ 579,150	$ 443,079
Stock-based compensation	24,590	18,322	12,753
Net tax benefit from stock-based compensation	894	4,602	7,877
Net cash provided by (used in) operating activities	478,845	722,582	648,293
Net cash provided by (used in) investing activities	(942,751)	(8,277,330)	(2,525,015)
Principal payments on long-term borrowings	0	0	(13,403)
Proceeds from stock option exercises	9,299	16,659	54,417
Purchase of treasury stock	(42,720)	(4,391)	(3,864)
Treasury stock issued to 401(k) stock purchase plan	0	0	1,749
Cash dividends paid on preferred stock	(6,675)	(6,675)	(7,157)
Cash dividends paid on common stock	(232,323)	(209,780)	(188,786)
Net cash provided by (used in) financing activities	(2,876,950)	2,999,880	8,170,869
Net change in cash and cash equivalents	(3,340,856)	(4,554,868)	6,294,147
Cash and cash equivalents at beginning of year	12,028,132	16,583,000	10,288,853
Cash and cash equivalents at end of year	8,687,276	12,028,132	16,583,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	597,973	579,150	443,079
Equity in undistributed earnings of subsidiaries	(331,761)	(538,439)	(232,727)
Stock-based compensation	880	720	700
Net tax benefit from stock-based compensation	331	472	278
Net change in other assets and other liabilities	19,867	(15,249)	23,890
Net cash provided by (used in) operating activities	287,290	26,654	235,220
Redemption of investment in non-bank subsidiary	0	0	406
Net cash provided by (used in) investing activities	0	0	406
Principal payments on long-term borrowings	0	0	(13,403)
Proceeds from stock option exercises	9,299	16,659	54,417
Proceeds from stock-based compensation activities of subsidiaries	23,710	17,602	12,053
Purchase of treasury stock	(42,720)	(4,391)	(3,864)
Treasury stock issued to 401(k) stock purchase plan	0	0	1,749
Cash dividends paid on preferred stock	(6,675)	(6,675)	(7,157)
Cash dividends paid on common stock	(232,323)	(209,780)	(188,786)
Net cash provided by (used in) financing activities	(248,709)	(186,585)	(144,991)
Net change in cash and cash equivalents	38,581	(159,931)	90,635
Cash and cash equivalents at beginning of year	311,944	471,875	381,240
Cash and cash equivalents at end of year	$ 350,525	$ 311,944	$ 471,875