Investment Securities - Reconciliation of Available-for-Sale and Held-to-Maturity Securities in Continuous Unrealized Loss Position (Detail) $ in Thousands	Mar. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Fair Value
Less Than 12 Months	$ 83,896	$ 472,731
12 Months or Longer	927,810	565,777
Total	$ 1,011,706	$ 1,038,508
Number of Securities | security	427	439
Unrealized Losses
Less Than 12 Months	$ 4,424	$ 33,764
12 Months or Longer	89,291	70,254
Total	93,715	104,018
Fair Value
Less Than 12 Months	70,038	129,018
12 Months or Longer	680,671	617,633
Total	750,709	746,651
Unrealized Losses
Less Than 12 Months	1,026	7,192
12 Months or Longer	138,889	155,731
Total	$ 139,915	$ 162,923
Number of Securities | security	568	581
U.S. government agencies
Fair Value
Less Than 12 Months	$ 13,915	$ 114,514
12 Months or Longer	319,832	229,094
Total	$ 333,747	$ 343,608
Number of Securities | security	62	67
Unrealized Losses
Less Than 12 Months	$ 30	$ 5,856
12 Months or Longer	23,760	22,563
Total	23,790	28,419
Fair Value
Less Than 12 Months	0	6,671
12 Months or Longer	9,115	2,412
Total	9,115	9,083
Unrealized Losses
Less Than 12 Months	0	336
12 Months or Longer	622	389
Total	$ 622	$ 725
Number of Securities | security	3	3
Mortgage-backed securities, residential
Fair Value
Less Than 12 Months	$ 5,635	$ 127,363
12 Months or Longer	301,414	182,079
Total	$ 307,049	$ 309,442
Number of Securities | security	134	135
Unrealized Losses
Less Than 12 Months	$ 315	$ 12,399
12 Months or Longer	36,300	28,349
Total	36,615	40,748
Fair Value
Less Than 12 Months	20,853	32,549
12 Months or Longer	274,937	264,035
Total	295,790	296,584
Unrealized Losses
Less Than 12 Months	849	2,275
12 Months or Longer	51,994	55,853
Total	$ 52,843	$ 58,128
Number of Securities | security	183	182
Collateralized mortgage obligations, residential
Fair Value
Less Than 12 Months	$ 16,300	$ 66,316
12 Months or Longer	135,417	87,742
Total	$ 151,717	$ 154,058
Number of Securities | security	104	104
Unrealized Losses
Less Than 12 Months	$ 503	$ 3,958
12 Months or Longer	13,566	12,486
Total	14,069	16,444
Fair Value
Less Than 12 Months	0	4,668
12 Months or Longer	10,488	5,787
Total	10,488	10,455
Unrealized Losses
Less Than 12 Months	0	516
12 Months or Longer	2,325	2,054
Total	$ 2,325	$ 2,570
Number of Securities | security	11	12
Mortgage-backed securities, multifamily
Fair Value
Less Than 12 Months	$ 0	$ 0
12 Months or Longer	788	786
Total	$ 788	$ 786
Number of Securities | security	1	1
Unrealized Losses
Less Than 12 Months	$ 0	$ 0
12 Months or Longer	206	215
Total	206	215
Fair Value
Less Than 12 Months	0
12 Months or Longer	4,406
Total	4,406
Unrealized Losses
Less Than 12 Months	0
12 Months or Longer	665
Total	$ 665
Number of Securities | security	4
Collateralized mortgage obligations, multifamily
Fair Value
Less Than 12 Months	$ 10,716	37,407
12 Months or Longer	35,706	8,926
Total	$ 46,422	$ 46,333
Number of Securities | security	20	20
Unrealized Losses
Less Than 12 Months	$ 141	$ 2,861
12 Months or Longer	4,129	1,914
Total	4,270	4,775
Fair Value
Less Than 12 Months		2,671
12 Months or Longer		1,676
Total		4,347
Unrealized Losses
Less Than 12 Months		376
12 Months or Longer		371
Total		$ 747
Number of Securities | security		4
Asset-backed securities
Fair Value
Less Than 12 Months	3,316	$ 34,871
12 Months or Longer	45,933	17,524
Total	$ 49,249	$ 52,395
Number of Securities | security	17	17
Unrealized Losses
Less Than 12 Months	$ 13	$ 977
12 Months or Longer	1,564	733
Total	1,577	1,710
Obligations of states and political subdivisions
Fair Value
Less Than 12 Months	1,214	3,771
12 Months or Longer	18,461	16,746
Total	$ 19,675	$ 20,517
Number of Securities | security	42	46
Unrealized Losses
Less Than 12 Months	$ 11	$ 276
12 Months or Longer	690	713
Total	701	989
Fair Value
Less Than 12 Months	49,185	82,459
12 Months or Longer	379,143	341,076
Total	428,328	423,535
Unrealized Losses
Less Than 12 Months	177	3,689
12 Months or Longer	82,865	96,711
Total	$ 83,042	$ 100,400
Number of Securities | security	366	379
Corporate bonds
Fair Value
Less Than 12 Months	$ 32,800	$ 88,489
12 Months or Longer	70,259	22,880
Total	$ 103,059	$ 111,369
Number of Securities | security	47	49
Unrealized Losses
Less Than 12 Months	$ 3,411	$ 7,437
12 Months or Longer	9,076	3,281
Total	12,487	$ 10,718
Fair Value
Less Than 12 Months	0
12 Months or Longer	2,582
Total	2,582
Unrealized Losses
Less Than 12 Months	0
12 Months or Longer	418
Total	$ 418
Number of Securities | security	1