Investment Securities - Reconciliation of Available-for-Sale and Held-to-Maturity Securities in Continuous Unrealized Loss Position (Detail) $ in Thousands	Mar. 31, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Fair Value
Less Than 12 Months	$ 1,006,835	$ 378,941
12 Months or Longer	40,990	38,045
Total	$ 1,047,825	$ 416,986
Number of Securities | security	352	94
Unrealized Losses
Less Than 12 Months	$ 38,694	$ 3,508
12 Months or Longer	2,458	923
Total	41,152	4,431
Fair Value
Less Than 12 Months	822,281	650,352
12 Months or Longer	5,021	2,376
Total	827,302	652,728
Unrealized Losses
Less Than 12 Months	80,395	11,684
12 Months or Longer	610	107
Total	$ 81,005	$ 11,791
Number of Securities | security	554	336
U.S. Treasury and U.S. government agencies
Fair Value
Less Than 12 Months	$ 329,916	$ 76,106
12 Months or Longer	18,066	14,670
Total	$ 347,982	$ 90,776
Number of Securities | security	58	15
Unrealized Losses
Less Than 12 Months	$ 12,391	$ 322
12 Months or Longer	1,125	467
Total	13,516	789
Fair Value
Less Than 12 Months	10,000
12 Months or Longer	0
Total	10,000
Unrealized Losses
Less Than 12 Months	248
12 Months or Longer	0
Total	$ 248
Number of Securities | security	3
Mortgage-backed securities, residential
Fair Value
Less Than 12 Months	$ 341,088	176,990
12 Months or Longer	12,992	14,582
Total	$ 354,080	$ 191,572
Number of Securities | security	110	45
Unrealized Losses
Less Than 12 Months	$ 15,974	$ 1,465
12 Months or Longer	843	266
Total	16,817	1,731
Fair Value
Less Than 12 Months	329,605	340,474
12 Months or Longer	5,021	2,376
Total	334,626	342,850
Unrealized Losses
Less Than 12 Months	26,834	5,882
12 Months or Longer	610	107
Total	$ 27,444	$ 5,989
Number of Securities | security	162	96
Collateralized mortgage obligations, residential
Fair Value
Less Than 12 Months	$ 158,210	$ 86,749
12 Months or Longer	4,645	5,000
Total	$ 162,855	$ 91,749
Number of Securities | security	78	18
Unrealized Losses
Less Than 12 Months	$ 6,557	$ 1,429
12 Months or Longer	102	59
Total	6,659	1,488
Fair Value
Less Than 12 Months	13,317
12 Months or Longer	0
Total	13,317
Unrealized Losses
Less Than 12 Months	1,116
12 Months or Longer	0
Total	$ 1,116
Number of Securities | security	12
Mortgage-backed securities, multifamily
Fair Value
Less Than 12 Months	$ 0	0
12 Months or Longer	1,603	1,741
Total	$ 1,603	$ 1,741
Number of Securities | security	1	1
Unrealized Losses
Less Than 12 Months	$ 0	$ 0
12 Months or Longer	206	75
Total	206	75
Fair Value
Less Than 12 Months	4,066
12 Months or Longer	0
Total	4,066
Unrealized Losses
Less Than 12 Months	204
12 Months or Longer	0
Total	$ 204
Number of Securities | security	3
Collateralized mortgage obligations, multifamily
Fair Value
Less Than 12 Months	$ 41,205	9,083
12 Months or Longer	797	1,072
Total	$ 42,002	$ 10,155
Number of Securities | security	16	4
Unrealized Losses
Less Than 12 Months	$ 1,832	$ 210
12 Months or Longer	69	36
Total	1,901	246
Fair Value
Less Than 12 Months		2,051
12 Months or Longer		0
Total		2,051
Unrealized Losses
Less Than 12 Months		2
12 Months or Longer		0
Total		$ 2
Number of Securities | security		1
Asset-backed securities
Fair Value
Less Than 12 Months	56,624	$ 14,688
12 Months or Longer	0	0
Total	$ 56,624	$ 14,688
Number of Securities | security	14	3
Unrealized Losses
Less Than 12 Months	$ 738	$ 87
12 Months or Longer	0	0
Total	738	87
Obligations of states and political subdivisions
Fair Value
Less Than 12 Months	21,427
12 Months or Longer	0
Total	$ 21,427
Number of Securities | security	46
Unrealized Losses
Less Than 12 Months	$ 590
12 Months or Longer	0
Total	590
Fair Value
Less Than 12 Months	462,388	307,827
12 Months or Longer	0	0
Total	462,388	307,827
Unrealized Losses
Less Than 12 Months	51,898	5,800
12 Months or Longer	0	0
Total	$ 51,898	$ 5,800
Number of Securities | security	373	239
Corporate bonds
Fair Value
Less Than 12 Months	$ 58,365	$ 15,325
12 Months or Longer	2,887	980
Total	$ 61,252	$ 16,305
Number of Securities | security	29	8
Unrealized Losses
Less Than 12 Months	$ 612	$ (5)
12 Months or Longer	113	20
Total	725	$ 15
Fair Value
Less Than 12 Months	2,905
12 Months or Longer	0
Total	2,905
Unrealized Losses
Less Than 12 Months	95
12 Months or Longer	0
Total	$ 95
Number of Securities | security	1