Fair Value Measurements - Summary of Fair Values of Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands		Mar. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value	[1]	$ 9,360,097	$ 9,006,600
Total derivative instruments, after netting		50,041	19,049
Originated loans held for sale		$ 688	$ 297
Derivative Liability Statement Of Financial Position Extensible Enumeration Not Disclosed Flag		true	true
Derivative Liability		$ 207,402	$ 279,600
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		9,360,097	9,006,600
Alternative investments measured at NAV		46,501	43,360
Total financial assets		9,682,732	9,365,837
Derivative Liability		260,590	311,561
Contingent consideration		12,682	11,750
Total financial liabilities		273,272	323,311
Fair Value, Recurring | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative instruments, after netting		262,349	302,142
Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Alternative investments measured at NAV		0	0
Total financial assets		13,249	14,701
Derivative Liability		588	43
Contingent consideration		0	0
Total financial liabilities		588	43
Fair Value, Recurring | Level 1 | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative instruments, after netting		152	1,263
Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		9,360,097	9,006,600
Alternative investments measured at NAV		0	0
Total financial assets		9,622,982	9,307,776
Derivative Liability		260,002	311,518
Contingent consideration		0	0
Total financial liabilities		260,002	311,518
Fair Value, Recurring | Level 2 | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative instruments, after netting		262,197	300,879
Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Alternative investments measured at NAV		0	0
Total financial assets		0	0
Derivative Liability		0	0
Contingent consideration		12,682	11,750
Total financial liabilities		12,682	11,750
Fair Value, Recurring | Level 3 | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative instruments, after netting		0	0
Originated loans held for sale | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Originated loans held for sale		688	297
Originated loans held for sale | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Originated loans held for sale		0	0
Originated loans held for sale | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Originated loans held for sale		688	297
Originated loans held for sale | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Originated loans held for sale		0	0
Investments held in Rabbi Trusts | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments held in Rabbi Trust		13,097	13,438
Investments held in Rabbi Trusts | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments held in Rabbi Trust		13,097	13,438
Investments held in Rabbi Trusts | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments held in Rabbi Trust		0	0
Investments held in Rabbi Trusts | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments held in Rabbi Trust		0	0
Government agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		192,341	186,426
Government agency debentures | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		192,341	186,426
Government agency debentures | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Government agency debentures | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		192,341	186,426
Government agency debentures | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Municipal bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		109,294	110,876
Municipal bonds and notes | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		109,294	110,876
Municipal bonds and notes | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Municipal bonds and notes | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		109,294	110,876
Municipal bonds and notes | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency CMO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		28,285	29,043
Agency CMO | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		28,285	29,043
Agency CMO | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency CMO | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		28,285	29,043
Agency CMO | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		4,758,155	4,519,785
Agency MBS | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		4,758,155	4,519,785
Agency MBS | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency MBS | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		4,758,155	4,519,785
Agency MBS | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency CMBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		3,156,300	3,034,392
Agency CMBS | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		3,156,300	3,034,392
Agency CMBS | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Agency CMBS | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		3,156,300	3,034,392
Agency CMBS | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
CMBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		629,351	625,388
CMBS | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		629,351	625,388
CMBS | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
CMBS | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		629,351	625,388
CMBS | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Corporate debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		437,930	452,266
Corporate debt | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		437,930	452,266
Corporate debt | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Corporate debt | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		437,930	452,266
Corporate debt | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Private label MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		39,158	39,219
Private label MBS | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		39,158	39,219
Private label MBS | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Private label MBS | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		39,158	39,219
Private label MBS | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		9,283	9,205
Other | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		9,283	9,205
Other | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		0	0
Other | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		9,283	9,205
Other | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale, at fair value		$ 0	$ 0

[1] Investment securities available-for-sale had an amortized cost basis of $9,941,377 at March 31, 2025, and $9,720,415 at December 31, 2024.