Securities - Summary of Contractual Maturities of Investment Securities Classified as Available for Sale and Held to Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Available for Sale, Amortized Cost
Due in one year or less	$ 12,005
Due after one year through five years	58,188
Due after five years through ten years	124,825
Due after ten years	57,541
Total	252,559
Amortized Cost	768,689	$ 839,272
Available for Sale, Fair Value
Due in one year or less	12,063
Due after one year through five years	58,409
Due after five years through ten years	125,735
Due after ten years	57,639
Total	253,846
Investment securities, available for sale, at fair value	769,956	855,746
Held to Maturity, Amortized Cost
Due in one year or less	21,345
Due after one year through five years	34,047
Due after five years through ten years	42,528
Due after ten years	340,339
Total	438,259
Amortized Cost	825,137
Held to Maturity, Fair Value
Due in one year or less	21,497
Due after one year through five years	34,192
Due after five years through ten years	42,315
Due after ten years	335,408
Total	433,412
Total securities, Held to Maturity, Fair Value	815,211	$ 93,868
Mortgage-backed securities
Available for Sale, Amortized Cost
Mortgage-backed and asset-backed securities	516,130
Available for Sale, Fair Value
Mortgage-backed and asset-backed securities	516,110
Held to Maturity, Amortized Cost
Mortgage-backed and asset-backed securities	386,878
Held to Maturity, Fair Value
Mortgage-backed and asset-backed securities	$ 381,799