Borrowed Funds - Remaining Contractual Maturities Of Repurchase Agreements (Detail) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	$ 2,454,868	$ 2,539,310
Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	1,925,648
2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	40,241	2,105,512
30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	485,979	431,048
Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	3,000	2,750
U.S. Treasury [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	299,192	608,836
U.S. Treasury [Member] | Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	299,192
U.S. Treasury [Member] | 2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements		608,836
U.S. Agencies [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	2,155,676	1,930,474
U.S. Agencies [Member] | Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	1,626,456
U.S. Agencies [Member] | 2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	40,241	1,496,676
U.S. Agencies [Member] | 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	485,979	431,048
U.S. Agencies [Member] | Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	$ 3,000	$ 2,750