Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Dec. 31, 2015 USD ($) holding	Dec. 31, 2014 USD ($) holding
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	$ 1,295,959	$ 259,477
Available for sale, Unrealized Losses - Less Than Twelve Months	(16,177)	(1,562)
Available for sale, Fair Value - Twelve Months or Longer	446,123	720,814
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (17,113)	$ (17,181)
Available for sale, Number of Holdings - Total | holding	156	94
Available for sale, Fair Value - Total	$ 1,742,082	$ 980,291
Available for sale, Unrealized Losses - Total	(33,290)	(18,743)
Held-to-maturity, Fair Value - Less Than Twelve Months	977,562	415,701
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(10,831)	(1,469)
Held-to-maturity, Fair Value - Twelve Months or Longer	542,714	702,497
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (14,581)	$ (12,823)
Held-to-maturity, Number of Holdings - Total | holding	152	89
Held-to-maturity, Fair Value - Total	$ 1,520,276	$ 1,118,198
Held-to-maturity, Unrealized Losses - Total	(25,412)	(14,292)
Agency collateralized mortgage obligations (agency CMO) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	195,369	47,217
Available for sale, Unrealized Losses - Less Than Twelve Months	(2,195)	(240)
Available for sale, Fair Value - Twelve Months or Longer	26,039	35,968
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (751)	$ (825)
Available for sale, Number of Holdings - Total | holding	14	8
Available for sale, Fair Value - Total	$ 221,408	$ 83,185
Available for sale, Unrealized Losses - Total	(2,946)	(1,065)
Held-to-maturity, Fair Value - Less Than Twelve Months	143,364	52,172
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(1,304)	(187)
Held-to-maturity, Fair Value - Twelve Months or Longer	27,928	24,942
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (754)	$ (552)
Held-to-maturity, Number of Holdings - Total | holding	13	6
Held-to-maturity, Fair Value - Total	$ 171,292	$ 77,114
Held-to-maturity, Unrealized Losses - Total	(2,058)	(739)
Agency mortgage-backed securities (agency MBS) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	481,839	3,691
Available for sale, Unrealized Losses - Less Than Twelve Months	(6,386)	(18)
Available for sale, Fair Value - Twelve Months or Longer	351,911	641,355
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (10,905)	$ (12,650)
Available for sale, Number of Holdings - Total | holding	84	64
Available for sale, Fair Value - Total	$ 833,750	$ 645,046
Available for sale, Unrealized Losses - Total	(17,291)	(12,668)
Held-to-maturity, Fair Value - Less Than Twelve Months	551,918	20,791
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(7,089)	(86)
Held-to-maturity, Fair Value - Twelve Months or Longer	470,828	608,568
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (12,819)	$ (11,254)
Held-to-maturity, Number of Holdings - Total | holding	87	44
Held-to-maturity, Fair Value - Total	$ 1,022,746	$ 629,359
Held-to-maturity, Unrealized Losses - Total	(19,908)	(11,340)
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	124,241	80,266
Available for sale, Unrealized Losses - Less Than Twelve Months	$ (959)	$ (134)
Available for sale, Number of Holdings - Total | holding	7	4
Available for sale, Fair Value - Total	$ 124,241	$ 80,266
Available for sale, Unrealized Losses - Total	(959)	(134)
Held-to-maturity, Fair Value - Less Than Twelve Months	110,864	324,394
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	$ (325)	$ (1,143)
Held-to-maturity, Number of Holdings - Total | holding	7	17
Held-to-maturity, Fair Value - Total	$ 110,864	$ 324,394
Held-to-maturity, Unrealized Losses - Total	(325)	(1,143)
Non-agency commercial mortgage-backed securities (non-agency CMBS) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	276,330	24,932
Available for sale, Unrealized Losses - Less Than Twelve Months	(2,879)	(117)
Available for sale, Fair Value - Twelve Months or Longer	19,382	9,396
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (26)	$ (6)
Available for sale, Number of Holdings - Total | holding	29	4
Available for sale, Fair Value - Total	$ 295,712	$ 34,328
Available for sale, Unrealized Losses - Total	(2,905)	(123)
Held-to-maturity, Fair Value - Less Than Twelve Months	142,382	13,003
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(1,983)	(30)
Held-to-maturity, Fair Value - Twelve Months or Longer	30,129	65,913
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (721)	$ (985)
Held-to-maturity, Number of Holdings - Total | holding	18	7
Held-to-maturity, Fair Value - Total	$ 172,511	$ 78,916
Held-to-maturity, Unrealized Losses - Total	(2,704)	(1,015)
Collateralized loan obligations (CLO) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	211,515	99,221
Available for sale, Unrealized Losses - Less Than Twelve Months	(2,709)	$ (1,017)
Available for sale, Fair Value - Twelve Months or Longer	15,708
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (561)
Available for sale, Number of Holdings - Total | holding	13	6
Available for sale, Fair Value - Total	$ 227,223	$ 99,221
Available for sale, Unrealized Losses - Total	(3,270)	(1,017)
Single issuer trust preferred securities [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	4,087	4,150
Available for sale, Unrealized Losses - Less Than Twelve Months	(128)	(36)
Available for sale, Fair Value - Twelve Months or Longer	33,083	34,095
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (4,870)	$ (3,700)
Available for sale, Number of Holdings - Total | holding	8	8
Available for sale, Fair Value - Total	$ 37,170	$ 38,245
Available for sale, Unrealized Losses - Total	(4,998)	(3,736)
Equity Securities [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	2,578
Available for sale, Unrealized Losses - Less Than Twelve Months	$ (921)
Available for sale, Number of Holdings - Total | holding	1
Available for sale, Fair Value - Total	$ 2,578
Available for sale, Unrealized Losses - Total	(921)
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held-to-maturity, Fair Value - Less Than Twelve Months	29,034	5,341
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(130)	(23)
Held-to-maturity, Fair Value - Twelve Months or Longer	13,829	3,074
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (287)	$ (32)
Held-to-maturity, Number of Holdings - Total | holding	27	15
Held-to-maturity, Fair Value - Total	$ 42,863	$ 8,415
Held-to-maturity, Unrealized Losses - Total	$ (417)	$ (55)