Investment Securities - Summary of Continuous Unrealized Loss Position of Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Investments [Line Items]
Fair Value, Less Than 12 Months, Available-for-sale	$ 2,344,856	$ 1,916,040
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale	(178,446)	(26,614)
Fair Value, 12 Months or Longer, Available-for-sale	1,188,776	97,989
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale	(168,365)	(3,274)
Fair Value, Available-for-sale	3,533,632	2,014,029
Gross Unrealized Holding Losses, Available-for-sale	(346,811)	(29,888)
Fair Value, Less Than 12 Months, Held-to-maturity	1,724,105
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity	(220,660)
Fair Value, 12 Months or Longer, Held-to-maturity	284,830
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity	(58,228)
Fair Value, Held-to-maturity	2,008,935
Gross Unrealized Holding Losses, Held-to-maturity	(278,888)
CMO/REMIC [Member]
Schedule of Investments [Line Items]
Fair Value, Less Than 12 Months, Available-for-sale	109,306	450,393
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale	(8,662)	(11,515)
Fair Value, 12 Months or Longer, Available-for-sale	378,651	53,745
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale	(58,939)	(2,468)
Fair Value, Available-for-sale	487,957	504,138
Gross Unrealized Holding Losses, Available-for-sale	(67,601)	(13,983)
Fair Value, Less Than 12 Months, Held-to-maturity	715,805
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity	(83,786)
Fair Value, 12 Months or Longer, Held-to-maturity
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity
Fair Value, Held-to-maturity	715,805
Gross Unrealized Holding Losses, Held-to-maturity	(83,786)
Mortgage-backed Securities [Member]
Schedule of Investments [Line Items]
Fair Value, Less Than 12 Months, Available-for-sale	2,212,757	1,465,647
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale	(168,634)	(15,099)
Fair Value, 12 Months or Longer, Available-for-sale	810,125	44,244
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale	(109,426)	(806)
Fair Value, Available-for-sale	3,022,882	1,509,891
Gross Unrealized Holding Losses, Available-for-sale	(278,060)	(15,905)
Fair Value, Less Than 12 Months, Held-to-maturity	552,966
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity	(73,582)
Fair Value, 12 Months or Longer, Held-to-maturity	4,209
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity	(762)
Fair Value, Held-to-maturity	557,175
Gross Unrealized Holding Losses, Held-to-maturity	(74,344)
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair Value, Less Than 12 Months, Available-for-sale	22,793	0
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale	(1,150)	0
Fair Value, 12 Months or Longer, Available-for-sale		0
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale	0	0
Fair Value, Available-for-sale	22,793	0
Gross Unrealized Holding Losses, Available-for-sale	(1,150)	$ 0
Fair Value, Less Than 12 Months, Held-to-maturity	221,355
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity	(26,968)
Fair Value, 12 Months or Longer, Held-to-maturity	54,397
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity	(11,122)
Fair Value, Held-to-maturity	275,752
Gross Unrealized Holding Losses, Held-to-maturity	(38,090)
Government Agency/GSE [Member]
Schedule of Investments [Line Items]
Fair Value, Less Than 12 Months, Held-to-maturity	233,979
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity	(36,324)
Fair Value, 12 Months or Longer, Held-to-maturity	226,224
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity	(46,344)
Fair Value, Held-to-maturity	460,203
Gross Unrealized Holding Losses, Held-to-maturity	$ (82,668)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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