Securities - Reconciliation of Available-for-Sale and Held-to-Maturity Securities in Continuous Unrealized Loss Position (Detail) $ in Thousands	Dec. 31, 2020 USD ($) security	Dec. 31, 2019 USD ($) security
Fair Value
Less than 12 Months	$ 174,022	$ 145,431
12 Months or Longer	23,308	152,543
Total	$ 197,330	$ 297,974
Number of Securities | security	61	105
Unrealized Losses
Less than 12 Months	$ 977	$ 720
12 Months or Longer	353	1,425
Total	1,330	2,145
Fair Value
Less than 12 Months	2,561	15,657
12 Months or Longer	0	16,692
Total	2,561	32,349
Unrealized Losses
Less than 12 Months	12	52
12 Months or Longer	0	134
Total	$ 12	$ 186
Number of Securities | security	4	19
U.S. Treasury and U.S. government agencies
Fair Value
Less than 12 Months	$ 4,966	$ 11,625
12 Months or Longer	17,652	41,617
Total	$ 22,618	$ 53,242
Number of Securities | security	6	11
Unrealized Losses
Less than 12 Months	$ 29	$ 39
12 Months or Longer	284	397
Total	313	436
Fair Value
Less than 12 Months		3,195
12 Months or Longer		5,102
Total		8,297
Unrealized Losses
Less than 12 Months		6
12 Months or Longer		2
Total		$ 8
Number of Securities | security		2
Mortgage-backed securities, residential
Fair Value
Less than 12 Months	84,137	$ 67,039
12 Months or Longer	5,656	64,509
Total	$ 89,793	$ 131,548
Number of Securities | security	30	48
Unrealized Losses
Less than 12 Months	$ 471	$ 313
12 Months or Longer	69	526
Total	540	839
Fair Value
Less than 12 Months	2,561	5,379
12 Months or Longer	0	8,060
Total	2,561	13,439
Unrealized Losses
Less than 12 Months	12	20
12 Months or Longer	0	101
Total	$ 12	$ 121
Number of Securities | security	4	10
Collateralized mortgage obligations, residential
Fair Value
Less than 12 Months	$ 23,858	$ 58,743
12 Months or Longer	0	34,980
Total	$ 23,858	$ 93,723
Number of Securities | security	7	38
Unrealized Losses
Less than 12 Months	$ 22	$ 248
12 Months or Longer	0	464
Total	22	712
Fair Value
Less than 12 Months		7,083
12 Months or Longer		2,532
Total		9,615
Unrealized Losses
Less than 12 Months		26
12 Months or Longer		29
Total		$ 55
Number of Securities | security		6
Mortgage-backed securities, multifamily
Fair Value
Less than 12 Months	1,943
12 Months or Longer	0
Total	$ 1,943
Number of Securities | security	1
Unrealized Losses
Less than 12 Months	$ 0
12 Months or Longer	0
Total	0
Fair Value
Less than 12 Months		$ 0
12 Months or Longer		998
Total		998
Unrealized Losses
Less than 12 Months		0
12 Months or Longer		2
Total		$ 2
Number of Securities | security		1
Collateralized mortgage obligations, multifamily
Fair Value
Less than 12 Months	2,527	$ 7,651
12 Months or Longer	0	4,878
Total	$ 2,527	$ 12,529
Number of Securities | security	1	3
Unrealized Losses
Less than 12 Months	$ 2	$ 118
12 Months or Longer	0	5
Total	2	123
Asset-backed securities
Fair Value
Less than 12 Months	40,690
12 Months or Longer	0
Total	$ 40,690
Number of Securities | security	6
Unrealized Losses
Less than 12 Months	$ 225
12 Months or Longer	0
Total	225
Obligations of states and political subdivisions
Fair Value
Less than 12 Months	15,901	373
12 Months or Longer	0	6,559
Total	$ 15,901	$ 6,932
Number of Securities | security	10	5
Unrealized Losses
Less than 12 Months	$ 228	$ 2
12 Months or Longer	0	33
Total	$ 228	$ 35