Fair Value - Quantitative Summary of Key Unobservable Inputs Used in Valuation of Interest Rate Lock Commitments (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Pull-Through Rate [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	52.10%	50.00%
Pull-Through Rate [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	99.00%	98.00%
Pull-Through Rate [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	87.30%	82.50%
Servicing Fee Multiple [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	2.00%	1.70%
Servicing Fee Multiple [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	8.20%	6.50%
Servicing Fee Multiple [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	5.30%	4.60%
Percentage of Unpaid Principal Balance [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	0.50%	0.40%
Percentage of Unpaid Principal Balance [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	2.60%	2.40%
Percentage of Unpaid Principal Balance [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Key inputs used in valuation of IRLCs	2.00%	1.70%
Interest Rate Lock Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 5,902	$ 7,532
Committed amount	$ 2,062,088	$ 874,017