Assets Sold Under Agreements to Repurchase - Summary of Maturities of Outstanding Advances Under Repurchase Agreements by Maturity Date (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	$ 5,751,519
Weighted average maturity (in months)	2 months 18 days
Within 30 days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	$ 287,565
Over 30 to 90 days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	4,071,705
Over 90 days to 180 days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	1,240,249
Over 180 Days to 1 Year [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	0
Over 1 year to 2 years [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Maturity of repurchase agreements	$ 152,000