Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Debt securities available for sale:
Due in one year or less	$ 131,291
Due after one year through five years	7,870,319
Due after five years through ten years	65,429
Due after ten years	30,000
Total available for sale (amortized cost)	8,097,039
Mortgage-backed securities available for sale	3,096,113
Investment securities available for sale, amortized cost	11,193,152	$ 3,849,347
Debt securities held to maturity:
Due in one year or less	137,854
Due after one year through five years	1,057,311
Due after five years through ten years	1,092,875
Due after ten years	1,344,838
Total available for held to maturity (amortized cost)	3,632,878
Mortgage-backed securities held to maturity	9,897,091
Amortized cost for held to maturity	13,529,969	2,734,674
Debt securities available for sale:
Due in one year or less	126,611
Due after one year through five years	7,628,579
Due after five years through ten years	61,938
Due after ten years	27,416
Total available for sale (fair value)	7,844,544
Mortgage-backed securities available for sale	2,904,417
Total	10,748,961	3,955,804
Debt securities held to maturity:
Due in one year or less	136,564
Due after one year through five years	1,011,114
Due after five years through ten years	1,068,369
Due after ten years	1,254,576
Total available for held to maturity (fair value)	3,470,623
Mortgage-backed securities held to maturity	8,904,797
Total	$ 12,375,420	$ 2,771,290