Securities - Summary Of Government-Sponsored Residential Mortgage-Backed Securities With Gross Unrealized Losses (Detail) $ in Thousands	Mar. 31, 2022 USD ($) holding	Dec. 31, 2021 USD ($) holding
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	672	470
Gross Unrealized Losses
Less than 12 Months	$ 325,829	$ 85,764
12 Months or Longer	216,542	26,683
Total	542,371	112,447
Fair Value
Less than 12 Months	5,428,387	5,993,147
12 Months or Longer	2,258,272	810,035
Total	$ 7,686,659	$ 6,803,182
Government-sponsored residential mortgage-backed securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	322	264
Gross Unrealized Losses
Less than 12 Months	$ 223,347	$ 70,502
12 Months or Longer	137,319	0
Total	360,666	70,502
Fair Value
Less than 12 Months	3,513,073	4,615,457
12 Months or Longer	1,403,234	0
Total	$ 4,916,307	$ 4,615,457
Government-sponsored commercial mortgage-backed securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	205	165
Gross Unrealized Losses
Less than 12 Months	$ 85,425	$ 12,218
12 Months or Longer	5,779	422
Total	91,204	12,640
Fair Value
Less than 12 Months	1,548,080	1,102,444
12 Months or Longer	67,847	15,682
Total	$ 1,615,927	$ 1,118,126
U.S. Agency bonds
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	37	27
Gross Unrealized Losses
Less than 12 Months	$ 12,573	$ 2,169
12 Months or Longer	73,444	26,261
Total	86,017	28,430
Fair Value
Less than 12 Months	226,708	191,222
12 Months or Longer	787,191	794,353
Total	$ 1,013,899	$ 985,575
U.S. Treasury securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	2	3
Gross Unrealized Losses
Less than 12 Months	$ 3,223	$ 834
12 Months or Longer	0	0
Total	3,223	834
Fair Value
Less than 12 Months	56,235	78,588
12 Months or Longer	0	0
Total	$ 56,235	$ 78,588
State and municipal bonds and obligations
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	103	11
Gross Unrealized Losses
Less than 12 Months	$ 1,245	$ 41
12 Months or Longer	0	0
Total	1,245	41
Fair Value
Less than 12 Months	82,709	5,436
12 Months or Longer	0	0
Total	$ 82,709	$ 5,436
Other debt securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	3
Gross Unrealized Losses
Less than 12 Months	$ 16
12 Months or Longer	0
Total	16
Fair Value
Less than 12 Months	1,582
12 Months or Longer	0
Total	$ 1,582