Investment Securities (Schedule Of Trust Preferred Securities - Pooled Issuers For OTTI Information) (Detail) (USD $) In Thousands, unless otherwise specified							6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Pooled Trust Preferred Securities [Member]		Dec. 31, 2012 Pooled Trust Preferred Securities [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class B [Member] Security H [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class B [Member] Security I [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class B [Member] Security J [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class B [Member] Security L [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class A [Member] Security K [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class A [Member] Security M [Member]		Jun. 30, 2013 Pooled Trust Preferred Securities [Member] Preferred Class A [Member] Security N [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	$ 3,253,001	$ 3,069,182	$ 44,025	[1],[2]	$ 46,018	[3]	$ 3,487	[2]	$ 4,468	[2]	$ 5,315	[2]	$ 8,726	[2]	$ 7,421	[2]	$ 7,139	[2]	$ 7,469	[2]
Gross Unrealized Losses	(58,758)	(31,489)	(13,810)	[1]	(19,811)	[3]	(1,178)		(1,520)		(2,027)		(3,061)		(2,447)		(3,045)		(532)
Available for sale - Fair Value	3,257,360	3,136,160	30,215	[1]	26,207	[3]	2,309		2,948		3,288		5,665		4,974		4,094		6,937
Lowest Credit Ratings							B	[4]	CCC	[4]	CCC	[4]	CCC	[4]	CCC	[4]	D	[4]	A	[4]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held							$ (352)		$ (365)		$ (806)		$ (867)		$ (2,040)		$ (4,926)		$ (1,104)
% of Performing Bank/Insurance Issuers							91.70%		87.50%		91.70%		91.30%		69.10%		60.70%		94.30%
Current Deferrals/Defaults (As a % of Original Collateral)							7.50%		17.20%		10.40%		13.20%		33.50%		34.60%		10.40%

[1] Amortized cost is net of $10.5 million of credit related other-than-temporary impairment at June 30, 2013.

[2] For the securities previously deemed impaired, the amortized cost is reflective of previous OTTI recognized in earnings.

[3] Amortized cost is net of $10.5 million of credit related other-than-temporary impairment at December 31, 2012.

[4] The Company utilized credit ratings provided by Moody’s, S&P and Fitch in its evaluation of issuers.