Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Dec. 31, 2022 USD ($) holding	Dec. 31, 2021 USD ($) holding
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 5,417,865	$ 2,272,641
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(532,120)	(17,086)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,429,126	558,515
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (332,369)	$ (17,256)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	1,282	162
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 7,846,991	$ 2,831,156
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(864,489)	(34,342)
Agency CMO
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	55,693	7,895
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(4,640)	$ (51)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,272
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (379)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	39	2
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 59,965	$ 7,895
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(5,019)	(51)
Agency MBS
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,641,544	506,602
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(206,412)	(7,354)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	515,206	110,687
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (96,927)	$ (3,666)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	460	70
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 2,156,750	$ 617,289
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(303,339)	(11,020)
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	485,333	632,213
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(68,674)	(6,163)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	921,153	335,480
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (189,440)	$ (12,381)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	132	28
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 1,406,486	$ 967,693
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(258,114)	(18,544)
CMBS
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	273,150	724,762
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8,982)	(1,744)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	598,490	81,253
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (23,966)	$ (139)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	52	50
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 871,640	$ 806,015
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(32,948)	(1,883)
CLO
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,107	21,848
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (1)	$ (13)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	1	1
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 2,107	$ 21,848
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1)	(13)
Corporate debt
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	692,990	4,203
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(89,692)	(76)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	8,421	9,247
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (1,895)	$ (1,057)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	105	3
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 701,411	$ 13,450
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(91,587)	(1,133)
U.S. Treasury notes
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	337,563	396,966
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(19,167)	$ (1,698)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	379,477
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (19,761)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	23	8
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 717,040	$ 396,966
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(38,928)	$ (1,698)
Government agency debentures
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	258,374
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (43,644)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	19
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 258,374
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(43,644)
Municipal bonds and notes
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,616,771
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (85,913)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	444
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 1,616,771
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(85,913)
Private label MBS
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	44,249
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (4,646)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	3
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 44,249
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(4,646)
Other
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	12,198
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (350)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	4
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 12,198
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (350)