Investment Securities (Summary Of Investment Securities) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Jun. 30, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Available for sale - Amortized cost	$ 2,853,070			$ 3,110,912
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	48,595			57,645
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(27,779)			(61,626)
Fair Value	2,873,886			3,106,931
Held to Maturity, Amortized Cost - Total debt securities	3,641,979			3,358,721
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	85,105			73,409
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(27,259)			(61,218)
Held to Maturity, Fair Value - Total debt securities	3,699,825			3,370,912
Other than temporary impairment	2,797		9,738	16,633		9,356	10,460	10,460
U.S. Treasury Bills [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	525			325
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	0			0
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	0			0
Fair Value	525			325
Agency collateralized mortgage obligations (CMOs) [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	628,737			794,397
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	10,543			14,383
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(1,057)			(1,868)
Fair Value	638,223			806,912
Held to Maturity, Amortized Cost - Total debt securities	411,128			365,081
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	7,374			10,135
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(1,409)			(1,009)
Held to Maturity, Fair Value - Total debt securities	417,093			374,207
Agency mortgage-backed securities (MBS) [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	1,103,345			1,265,276
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	11,014			9,124
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(23,539)			(47,698)
Fair Value	1,090,820			1,226,702
Held to Maturity, Amortized Cost - Total debt securities	2,181,225			2,130,685
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	52,799			43,315
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(23,068)			(53,188)
Held to Maturity, Fair Value - Total debt securities	2,210,956			2,120,812
Agency commercial mortgage-backed securities (ACMBS) [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	80,732			71,759
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	0			0
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(349)			(782)
Fair Value	80,383			70,977
Held to Maturity, Amortized Cost - Total debt securities	377,382			115,995
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	650			44
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(622)			(818)
Held to Maturity, Fair Value - Total debt securities	377,410			115,221
Commercial mortgage-backed securities (CMBS) [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	510,922			436,872
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	21,975			28,398
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(55)			(996)
Fair Value	532,842			464,274
Held to Maturity, Amortized Cost - Total debt securities	288,692			290,057
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	8,833			8,635
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(2,122)			(4,975)
Held to Maturity, Fair Value - Total debt securities	295,403			293,717
Collateralized loan obligations (CLOs) [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	379,741	[1]		357,326	[2]
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	912	[1]		315	[2]
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(142)	[1]		0	[2]
Fair Value	380,511	[1]		357,641	[2]
Other than temporary impairment	2,800			2,600
Pooled trust preferred securities [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	0			31,900	[3]
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	0			0	[3]
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	0	[3]		(3,410)	[3]
Fair Value	0			28,490	[3]
Other than temporary impairment				(14,000)
Single issuer trust preferred securities [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	41,936			41,807
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	83			0
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	(2,637)			(6,872)
Fair Value	39,382			34,935
Corporate debt securities [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	107,132			108,936
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	4,068			4,155
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	0			0
Fair Value	111,200			113,091
Equity securities - financial institutions [Member]
Schedule of Investments [Line Items]
Available for sale - Amortized cost	0			2,314	[4]
Available-for-sale - Recognized in OCI - Gross Unrealized Gains	0			1,270	[4]
Available-for-sale - Recognized in OCI - Gross Unrealized Losses	0			0	[4]
Fair Value	0			3,584	[4]
Other than temporary impairment				20,400
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost - Total debt securities	377,074			448,405
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	15,332			11,104
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	(38)			(1,228)
Held to Maturity, Fair Value - Total debt securities	392,368			458,281
Private Label MBS [Member]
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost - Total debt securities	6,478			8,498
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Gains	117			176
Held-to-maturity - Not Recognized in OCI - Gross Unrealized Losses	0			0
Held to Maturity, Fair Value - Total debt securities	$ 6,595			$ 8,674

[1] Amortized cost is net of $2.8 million of other-than-temporary impairments at September 30, 2014.

[2] Amortized cost is net of $2.6 million of other-than-temporary impairments at December 31, 2013.

[3] Amortized cost is net of $14.0 million of other-than-temporary impairments at December 31, 2013.

[4] Amortized cost is net of $20.4 million of other-than-temporary impairments at December 31, 2013.