Investment Securities - Reconciliation of Available-for-Sale Securities (Detail) $ in Thousands	Jun. 30, 2023 USD ($) security	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) security	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,094,955		$ 1,158,534
Gross Unrealized Gains	119		106
Gross Unrealized Losses	(106,101)		(104,018)
Allowance for Credit Losses	0	$ (160)	(310)	$ (2,802)	$ (1,267)	$ (83)
Total	988,973		1,054,312
Less Than 12 Months	56,616		129,018
Less Than 12 Months	1,315		7,192
12 Months or Longer	662,770		617,633
12 Months or Longer	$ 147,045		$ 155,731
Number of Securities | security	563		581
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 719,386		$ 746,651
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	148,360		162,923
U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	359,909		383,958
Gross Unrealized Gains	105		100
Gross Unrealized Losses	(26,323)		(28,419)
Allowance for Credit Losses	0		0
Total	333,691		355,639
Less Than 12 Months	0		6,671
Less Than 12 Months	0		336
12 Months or Longer	8,897		2,412
12 Months or Longer	$ 699		$ 389
Number of Securities | security	3		3
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 8,897		$ 9,083
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	699		725
Mortgage-backed securities, residential
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	337,275		351,355
Gross Unrealized Gains	0		6
Gross Unrealized Losses	(39,471)		(40,748)
Allowance for Credit Losses	0		0
Total	297,804		310,613
Less Than 12 Months	22,367		32,549
Less Than 12 Months	1,160		2,275
12 Months or Longer	264,797		264,035
12 Months or Longer	$ 55,063		$ 55,853
Number of Securities | security	187		182
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 287,164		$ 296,584
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	56,223		58,128
Collateralized mortgage obligations, residential
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	160,507		170,502
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(16,070)		(16,444)
Allowance for Credit Losses	0		0
Total	144,437		154,058
Less Than 12 Months	0		4,668
Less Than 12 Months	0		516
12 Months or Longer	10,075		5,787
12 Months or Longer	$ 2,586		$ 2,054
Number of Securities | security	11		12
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 10,075		$ 10,455
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	2,586		2,570
Mortgage-backed securities, multifamily
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	989		1,000
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(221)		(215)
Allowance for Credit Losses	0		0
Total	768		785
Less Than 12 Months	0		2,671
Less Than 12 Months	0		376
12 Months or Longer	4,307		1,676
12 Months or Longer	$ 741		$ 371
Number of Securities | security	4		4
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 4,307		$ 4,347
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	741		747
Collateralized mortgage obligations, multifamily
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	50,183		51,108
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(4,846)		(4,775)
Allowance for Credit Losses	0		0
Total	45,337		46,333
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	48,566		54,105
Gross Unrealized Gains	14		0
Gross Unrealized Losses	(1,117)		(1,710)
Allowance for Credit Losses	0		0
Total	47,463		52,395
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	21,875		22,112
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(838)		(989)
Allowance for Credit Losses	0		(1)
Total	21,037		21,122
Less Than 12 Months	34,249		82,459
Less Than 12 Months	155		3,689
12 Months or Longer	372,367		341,076
12 Months or Longer	$ 87,283		$ 96,711
Number of Securities | security	357		379
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 406,616		$ 423,535
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	87,438		100,400
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	115,651		124,394
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(17,215)		(10,718)
Allowance for Credit Losses	0		(309)
Total	98,436		113,367
Less Than 12 Months	0		0
Less Than 12 Months	0		0
12 Months or Longer	2,327		2,647
12 Months or Longer	$ 673		$ 353
Number of Securities | security	1		1
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value	$ 2,327		$ 2,647
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Accumulated Loss	$ 673		$ 353