Borrowed Funds - Remaining Contractual Maturities Of Repurchase Agreements (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	$ 2,191,293	$ 2,105,831
2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	1,917,287	1,830,542
30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	194,506	186,289
Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	79,500	89,000
U.S. Treasury [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	218,989	163,146
U.S. Treasury [Member] | 2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	182,760	119,528
U.S. Treasury [Member] | Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	36,229	43,618
U.S. Agencies [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	1,972,304	1,942,685
U.S. Agencies [Member] | 2 to 29 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	1,734,527	1,711,014
U.S. Agencies [Member] | 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	194,506	186,289
U.S. Agencies [Member] | Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total repurchase agreements	$ 43,271	$ 45,382