Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014 holding	Dec. 31, 2013 holding
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	$ 221,237	$ 893,274
Available for sale, Unrealized Losses - Less Than Twelve Months	(811)	(33,409)
Available for sale, Fair Value - Twelve Months or Longer	790,414	330,990
Available for sale, Unrealized Losses - Twelve Months or Longer	(26,968)	(28,217)
Available for sale, Number of Holdings - Total	99	123
Available for sale, Fair Value - Total	1,011,651	1,224,264
Available for sale, Unrealized Losses - Total	(27,779)	(61,626)
Held-to-maturity, Fair Value - Less Than Twelve Months	575,621	1,342,814
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(2,597)	(49,260)
Held-to-maturity, Fair Value - Twelve Months or Longer	773,954	187,778
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	(24,662)	(11,958)
Held-to-maturity, Number of Holdings - Total	105	164
Held-to-maturity, Fair Value - Total	1,349,575	1,530,592
Held-to-maturity, Unrealized Losses - Total	(27,259)	(61,218)
Agency CMOs [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	82,646	149,894
Available for sale, Unrealized Losses - Less Than Twelve Months	(278)	(1,713)
Available for sale, Fair Value - Twelve Months or Longer	35,915	9,011
Available for sale, Unrealized Losses - Twelve Months or Longer	(779)	(155)
Available for sale, Number of Holdings - Total	10	15
Available for sale, Fair Value - Total	118,561	158,905
Available for sale, Unrealized Losses - Total	(1,057)	(1,868)
Held-to-maturity, Fair Value - Less Than Twelve Months	111,069	53,789
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(798)	(1,009)
Held-to-maturity, Fair Value - Twelve Months or Longer	25,943
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	(611)
Held-to-maturity, Number of Holdings - Total	10	4
Held-to-maturity, Fair Value - Total	137,012	53,789
Held-to-maturity, Unrealized Losses - Total	(1,409)	(1,009)
Agency MBS [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	55,408	616,286
Available for sale, Unrealized Losses - Less Than Twelve Months	(262)	(29,537)
Available for sale, Fair Value - Twelve Months or Longer	665,932	279,680
Available for sale, Unrealized Losses - Twelve Months or Longer	(23,277)	(18,161)
Available for sale, Number of Holdings - Total	73	88
Available for sale, Fair Value - Total	721,340	895,966
Available for sale, Unrealized Losses - Total	(23,539)	(47,698)
Held-to-maturity, Fair Value - Less Than Twelve Months	258,608	1,045,693
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(1,161)	(42,181)
Held-to-maturity, Fair Value - Twelve Months or Longer	671,769	170,780
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	(21,907)	(11,007)
Held-to-maturity, Number of Holdings - Total	64	94
Held-to-maturity, Fair Value - Total	930,377	1,216,473
Held-to-maturity, Unrealized Losses - Total	(23,068)	(53,188)
Agency CMBS [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	36,325	70,977
Available for sale, Unrealized Losses - Less Than Twelve Months	(88)	(782)
Available for sale, Fair Value - Twelve Months or Longer	44,057
Available for sale, Unrealized Losses - Twelve Months or Longer	(261)
Available for sale, Number of Holdings - Total	4	3
Available for sale, Fair Value - Total	80,382	70,977
Available for sale, Unrealized Losses - Total	(349)	(782)
Held-to-maturity, Fair Value - Less Than Twelve Months	196,139	90,218
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(622)	(818)
Held-to-maturity, Fair Value - Twelve Months or Longer
Held-to-maturity, Unrealized Losses, Twelve Months or Longer
Held-to-maturity, Number of Holdings - Total	9	4
Held-to-maturity, Fair Value - Total	196,139	90,218
Held-to-maturity, Unrealized Losses - Total	(622)	(818)
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held-to-maturity, Fair Value - Less Than Twelve Months	4,311	46,587
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(6)	(1,193)
Held-to-maturity, Fair Value - Twelve Months or Longer	3,075	2,166
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	(32)	(35)
Held-to-maturity, Number of Holdings - Total	14	51
Held-to-maturity, Fair Value - Total	7,386	48,753
Held-to-maturity, Unrealized Losses - Total	(38)	(1,228)
CMBS [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	15,000	52,340
Available for sale, Unrealized Losses - Less Than Twelve Months	(41)	(996)
Available for sale, Fair Value - Twelve Months or Longer	9,390
Available for sale, Unrealized Losses - Twelve Months or Longer	(14)
Available for sale, Number of Holdings - Total	3	7
Available for sale, Fair Value - Total	24,390	52,340
Available for sale, Unrealized Losses - Total	(55)	(996)
Held-to-maturity, Fair Value - Less Than Twelve Months	5,494	106,527
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(10)	(4,059)
Held-to-maturity, Fair Value - Twelve Months or Longer	73,167	14,832
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	(2,112)	(916)
Held-to-maturity, Number of Holdings - Total	8	11
Held-to-maturity, Fair Value - Total	78,661	121,359
Held-to-maturity, Unrealized Losses - Total	(2,122)	(4,975)
Collateralized loan obligations (CLOs) [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months	31,858
Available for sale, Unrealized Losses - Less Than Twelve Months	(142)
Available for sale, Fair Value - Twelve Months or Longer
Available for sale, Unrealized Losses - Twelve Months or Longer
Available for sale, Number of Holdings - Total	2
Available for sale, Fair Value - Total	31,858
Available for sale, Unrealized Losses - Total	(142)
Pooled trust preferred securities [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months		0
Available for sale, Unrealized Losses - Less Than Twelve Months
Available for sale, Fair Value - Twelve Months or Longer		11,141
Available for sale, Unrealized Losses - Twelve Months or Longer		(3,410)
Available for sale, Number of Holdings - Total		2
Available for sale, Fair Value - Total		11,141
Available for sale, Unrealized Losses - Total		(3,410)
Single issuer trust preferred securities [Member]
Schedule of Investments [Line Items]
Available for Sale, Fair Value - Less Than Twelve Months		3,777
Available for sale, Unrealized Losses - Less Than Twelve Months		(381)
Available for sale, Fair Value - Twelve Months or Longer	35,120	31,158
Available for sale, Unrealized Losses - Twelve Months or Longer	(2,637)	(6,491)
Available for sale, Number of Holdings - Total	7	8
Available for sale, Fair Value - Total	35,120	34,935
Available for sale, Unrealized Losses - Total	$ (2,637)	$ (6,872)