Investment Securities - Reconciliation of Available-for-Sale and Held-to-Maturity Securities in Continuous Unrealized Loss Position (Detail) $ in Thousands	Jun. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Fair Value
Less Than 12 Months	$ 39,554	$ 472,731
12 Months or Longer	931,860	565,777
Total	$ 971,414	$ 1,038,508
Number of Securities | security	421	439
Unrealized Losses
Less Than 12 Months	$ 2,318	$ 33,764
12 Months or Longer	103,783	70,254
Total	106,101	104,018
Fair Value
Less Than 12 Months	56,616	129,018
12 Months or Longer	662,770	617,633
Total	719,386	746,651
Unrealized Losses
Less Than 12 Months	1,315	7,192
12 Months or Longer	147,045	155,731
Total	$ 148,360	$ 162,923
Number of Securities | security	563	581
U.S. government agencies
Fair Value
Less Than 12 Months	$ 13,654	$ 114,514
12 Months or Longer	306,321	229,094
Total	$ 319,975	$ 343,608
Number of Securities | security	60	67
Unrealized Losses
Less Than 12 Months	$ 26	$ 5,856
12 Months or Longer	26,297	22,563
Total	26,323	28,419
Fair Value
Less Than 12 Months	0	6,671
12 Months or Longer	8,897	2,412
Total	8,897	9,083
Unrealized Losses
Less Than 12 Months	0	336
12 Months or Longer	699	389
Total	$ 699	$ 725
Number of Securities | security	3	3
Mortgage-backed securities, residential
Fair Value
Less Than 12 Months	$ 6,258	$ 127,363
12 Months or Longer	291,546	182,079
Total	$ 297,804	$ 309,442
Number of Securities | security	134	135
Unrealized Losses
Less Than 12 Months	$ 393	$ 12,399
12 Months or Longer	39,078	28,349
Total	39,471	40,748
Fair Value
Less Than 12 Months	22,367	32,549
12 Months or Longer	264,797	264,035
Total	287,164	296,584
Unrealized Losses
Less Than 12 Months	1,160	2,275
12 Months or Longer	55,063	55,853
Total	$ 56,223	$ 58,128
Number of Securities | security	187	182
Collateralized mortgage obligations, residential
Fair Value
Less Than 12 Months	$ 8,929	$ 66,316
12 Months or Longer	135,508	87,742
Total	$ 144,437	$ 154,058
Number of Securities | security	100	104
Unrealized Losses
Less Than 12 Months	$ 505	$ 3,958
12 Months or Longer	15,565	12,486
Total	16,070	16,444
Fair Value
Less Than 12 Months	0	4,668
12 Months or Longer	10,075	5,787
Total	10,075	10,455
Unrealized Losses
Less Than 12 Months	0	516
12 Months or Longer	2,586	2,054
Total	$ 2,586	$ 2,570
Number of Securities | security	11	12
Mortgage-backed securities, multifamily
Fair Value
Less Than 12 Months	$ 0	$ 0
12 Months or Longer	768	786
Total	$ 768	$ 786
Number of Securities | security	1	1
Unrealized Losses
Less Than 12 Months	$ 0	$ 0
12 Months or Longer	221	215
Total	221	215
Fair Value
Less Than 12 Months	0	2,671
12 Months or Longer	4,307	1,676
Total	4,307	4,347
Unrealized Losses
Less Than 12 Months	0	376
12 Months or Longer	741	371
Total	$ 741	$ 747
Number of Securities | security	4	4
Collateralized mortgage obligations, multifamily
Fair Value
Less Than 12 Months	$ 7	$ 37,407
12 Months or Longer	45,330	8,926
Total	$ 45,337	$ 46,333
Number of Securities | security	20	20
Unrealized Losses
Less Than 12 Months	$ 0	$ 2,861
12 Months or Longer	4,846	1,914
Total	4,846	4,775
Asset-backed securities
Fair Value
Less Than 12 Months	0	34,871
12 Months or Longer	44,361	17,524
Total	$ 44,361	$ 52,395
Number of Securities | security	14	17
Unrealized Losses
Less Than 12 Months	$ 0	$ 977
12 Months or Longer	1,117	733
Total	1,117	1,710
Obligations of states and political subdivisions
Fair Value
Less Than 12 Months	2,055	3,771
12 Months or Longer	18,242	16,746
Total	$ 20,297	$ 20,517
Number of Securities | security	45	46
Unrealized Losses
Less Than 12 Months	$ 45	$ 276
12 Months or Longer	793	713
Total	838	989
Fair Value
Less Than 12 Months	34,249	82,459
12 Months or Longer	372,367	341,076
Total	406,616	423,535
Unrealized Losses
Less Than 12 Months	155	3,689
12 Months or Longer	87,283	96,711
Total	$ 87,438	$ 100,400
Number of Securities | security	357	379
Corporate bonds
Fair Value
Less Than 12 Months	$ 8,651	$ 88,489
12 Months or Longer	89,784	22,880
Total	$ 98,435	$ 111,369
Number of Securities | security	47	49
Unrealized Losses
Less Than 12 Months	$ 1,349	$ 7,437
12 Months or Longer	15,866	3,281
Total	17,215	10,718
Fair Value
Less Than 12 Months	0	0
12 Months or Longer	2,327	2,647
Total	2,327	2,647
Unrealized Losses
Less Than 12 Months	0	0
12 Months or Longer	673	353
Total	$ 673	$ 353
Number of Securities | security	1	1