Other Comprehensive Income - Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023
Pre Tax Amount
Total other comprehensive (loss) income	$ (124,275)	$ (310,220)	$ 279,345	$ (779,050)
Tax Benefit (Expense)
Total other comprehensive (loss) income	33,157	61,711	(57,135)	174,583
After Tax Amount
Before reclassifications			(50,539)	(599,294)
Less: reclassification adjustments			(272,749)	5,173
Total other comprehensive (loss) income	(91,118)	(248,509)	222,210	(604,467)
Total realized gain, net of tax					$ 41,200
Balance of gain after amortization, net of tax		1,300		1,300
Unrealized losses on securities available for sale:
Pre Tax Amount
Before reclassifications	(78,810)	(307,893)	(36,509)	(773,425)
Less: reclassification adjustments	0	(104)	(333,170)	(2,276)
Total other comprehensive (loss) income	(78,810)	(307,789)	296,661	(771,149)
Tax Benefit (Expense)
Before reclassifications	20,324	61,043	11,514	173,051
Less: reclassification adjustments	0	29	74,630	702
Total other comprehensive (loss) income	20,324	61,014	(63,116)	172,349
After Tax Amount
Before reclassifications	(58,486)	(246,850)	(24,995)	(600,374)
Less: reclassification adjustments	0	(75)	(258,540)	(1,574)
Total other comprehensive (loss) income	(58,486)	(246,775)	233,545	(598,800)
Unrealized gains (losses) on cash flow hedges
Pre Tax Amount
Before reclassifications	(56,892)	1,485	(37,146)	1,485
Less: reclassification adjustments	(11,929)	3,744	(20,834)	9,042
Total other comprehensive (loss) income	(44,963)	(2,259)	(16,312)	(7,557)
Tax Benefit (Expense)
Before reclassifications	16,060	(405)	11,602	(405)
Less: reclassification adjustments	3,368	(1,053)	5,883	(2,542)
Total other comprehensive (loss) income	12,692	648	5,719	2,137
After Tax Amount
Before reclassifications	(40,832)	1,080	(25,544)	1,080
Less: reclassification adjustments	(8,561)	2,691	(14,951)	6,500
Total other comprehensive (loss) income	(32,271)	(1,611)	(10,593)	(5,420)
Defined benefit pension plans:
Pre Tax Amount
Total other comprehensive (loss) income	(502)	(172)	(1,004)	(344)
Tax Benefit (Expense)
Total other comprehensive (loss) income	141	49	262	97
After Tax Amount
Before reclassifications			0	0
Less: reclassification adjustments			742	247
Total other comprehensive (loss) income	(361)	(123)	(742)	(247)
Change in actuarial net loss
Pre Tax Amount
Before reclassifications	0	0	0	0
Tax Benefit (Expense)
Before reclassifications	0	0	0	0
After Tax Amount
Before reclassifications	0	0	0	0
Less: amortization of actuarial net loss
Pre Tax Amount
Less: reclassification adjustments	(2,468)	(2,798)	(4,936)	(5,596)
Tax Benefit (Expense)
Less: reclassification adjustments	697	786	1,394	1,573
After Tax Amount
Less: reclassification adjustments	(1,771)	(2,012)	(3,542)	(4,023)
Less: accretion of prior service credit
Pre Tax Amount
Less: reclassification adjustments	2,970	2,970	5,940	5,940
Tax Benefit (Expense)
Less: reclassification adjustments	(838)	(835)	(1,656)	(1,670)
After Tax Amount
Less: reclassification adjustments	$ 2,132	$ 2,135	$ 4,284	$ 4,270