Securities - Summary Of Fair Value Of Available For Sale Securities By Contractual Maturities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	$ 51,955	$ 50,429
Due in one year or less, Fair value	51,932	50,659
Due after one year to five years, Amortized Cost	784,326	186,659
Due after one year to five years, Fair value	773,349	190,308
Due after five to ten years, Amortized Cost	2,023,620	759,068
Due after five to ten years, Fair value	1,994,423	763,869
Due after ten years, Amortized Cost	5,727,278	2,129,028
Due after ten years, Fair value	5,691,520	2,179,025
Total Amortized Cost	8,587,179	3,125,184
Fair Value	8,511,224	3,183,861
Government-sponsored residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	0	0
Due in one year or less, Fair value	0	0
Due after one year to five years, Amortized Cost	24,935	46,293
Due after one year to five years, Fair value	25,962	48,925
Due after five to ten years, Amortized Cost	899,169	96,338
Due after five to ten years, Fair value	892,029	100,278
Due after ten years, Amortized Cost	4,653,188	1,964,027
Due after ten years, Fair value	4,606,717	1,999,597
Total Amortized Cost	5,577,292	2,106,658
Fair Value	5,524,708	2,148,800
Government-sponsored commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	0	0
Due in one year or less, Fair value	0	0
Due after one year to five years, Amortized Cost	139,095	0
Due after one year to five years, Fair value	137,755	0
Due after five to ten years, Amortized Cost	387,177	17,054
Due after five to ten years, Fair value	378,414	17,081
Due after ten years, Amortized Cost	894,476	0
Due after ten years, Fair value	892,699	0
Total Amortized Cost	1,420,748	17,054
Fair Value	1,408,868	17,081
U.S. Agency bonds
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	5,508	0
Due in one year or less, Fair value	5,515	0
Due after one year to five years, Amortized Cost	531,821	99,772
Due after one year to five years, Fair value	520,935	99,834
Due after five to ten years, Amortized Cost	665,048	570,696
Due after five to ten years, Fair value	648,564	566,875
Due after ten years, Amortized Cost	0	0
Due after ten years, Fair value	0	0
Total Amortized Cost	1,202,377	670,468
Fair Value	1,175,014	666,709
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	40,010	50,023
Due in one year or less, Fair value	40,001	50,251
Due after one year to five years, Amortized Cost	49,424	20,083
Due after one year to five years, Fair value	48,604	20,118
Due after five to ten years, Amortized Cost	0	0
Due after five to ten years, Fair value	0	0
Due after ten years, Amortized Cost	0	0
Due after ten years, Fair value	0	0
Total Amortized Cost	89,434	70,106
Fair Value	88,605	70,369
State and municipal bonds and obligations
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	6,137	406
Due in one year or less, Fair value	6,116	408
Due after one year to five years, Amortized Cost	33,692	20,511
Due after one year to five years, Fair value	34,704	21,431
Due after five to ten years, Amortized Cost	72,226	74,980
Due after five to ten years, Fair value	75,416	79,635
Due after ten years, Amortized Cost	151,855	165,001
Due after ten years, Fair value	164,093	179,428
Total Amortized Cost	263,910	260,898
Fair Value	280,329	$ 280,902
Small Business Administration pooled securities
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	0
Due in one year or less, Fair value	0
Due after one year to five years, Amortized Cost	4,062
Due after one year to five years, Fair value	4,092
Due after five to ten years, Amortized Cost	0
Due after five to ten years, Fair value	0
Due after ten years, Amortized Cost	27,759
Due after ten years, Fair value	28,011
Total Amortized Cost	31,821
Fair Value	32,103
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	300
Due in one year or less, Fair value	300
Due after one year to five years, Amortized Cost	1,297
Due after one year to five years, Fair value	1,297
Due after five to ten years, Amortized Cost	0
Due after five to ten years, Fair value	0
Due after ten years, Amortized Cost	0
Due after ten years, Fair value	0
Total Amortized Cost	1,597
Fair Value	$ 1,597