Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Dec. 31, 2021 USD ($) holding	Dec. 31, 2020 USD ($) holding
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 2,272,641	$ 894,628
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(17,086)	(7,699)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	558,515	61,347
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (17,256)	$ (1,772)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	162	88
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 2,831,156	$ 955,975
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(34,342)	(9,471)
US Treasury and Government
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	396,966
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,698)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	8
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 396,966
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,698)
Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	7,895	13,137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(51)	(49)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	5,944
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0	$ (49)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	2	5
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 7,895	$ 19,081
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(51)	(98)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	506,602	33,742
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(7,354)	(219)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	110,687	4,561
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (3,666)	$ (70)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	70	30
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 617,289	$ 38,303
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(11,020)	(289)
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	632,213	376,330
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6,163)	(1,514)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	335,480	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (12,381)	$ 0
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	28	8
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 967,693	$ 376,330
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(18,544)	(1,514)
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	724,762	409,591
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,744)	(5,486)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	81,253	23,167
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (139)	$ (337)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	50	38
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 806,015	$ 432,758
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,883)	(5,823)
Collateralized loan obligations (CLO) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		57,728
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(265)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	21,848	18,655
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (13)	$ (45)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	1	4
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 21,848	$ 76,383
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(13)	(310)
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,203	4,100
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(76)	(166)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	9,247	9,020
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (1,057)	$ (1,271)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	3	3
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 13,450	$ 13,120
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (1,133)	$ (1,437)

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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