Fair Value Information - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	$ 3,626,157	$ 3,183,923
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets	503,411	656,551
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	582
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	26,089	29,468
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	0	0
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,626,157	3,183,923
Interest rate swaps, assets	582	14,163
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets	582	14,163
Total liabilities	582
Fair Value on Recurring Basis [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		0
Total liabilities		0
Fair Value on Recurring Basis [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	3,626,739	3,198,086
Total liabilities		14,163
Fair Value on Recurring Basis [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Total liabilities	0	0
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	26,089	29,468
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,108,915	2,563,214
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	490,130	590,158
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,023	1,083
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,626,157	3,183,923
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets		0
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets		0
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	582	14,163
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets	582	14,163
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	0	0
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets	0	0
Fair Value on Recurring Basis [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	3,626,739	3,198,086
Total liabilities		14,163
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	26,089	29,468
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,108,915	2,563,214
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | CMO/REMIC - Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	490,130	590,158
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,023	1,083
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Investment Securities-AFS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,626,157	3,183,923
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	582	14,163
Financial liabilities, Net Amounts of Assets Presented in the Condensed Consolidated Balance Sheets	$ 582	$ 14,163