Investment Securities (Summary Of Available For Sale Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 3,140,282	[1]	$ 3,224,749	[1]
Gross Unrealized Gains	21,368		19,170
Gross Unrealized Losses	(29,248)		(44,561)
Fair Value	3,132,402		3,199,358
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,792	[1]	17,791	[1]
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Fair Value	17,792		17,791
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,276	[1]	33,480	[1]
Gross Unrealized Gains	1,117		1,161
Gross Unrealized Losses	0		0
Fair Value	34,393		34,641
Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	112,051	[1]	112,305	[1]
Gross Unrealized Gains	1,269		1,440
Gross Unrealized Losses	0		0
Fair Value	113,320		113,745
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	170,326	[1]	196,521	[1]
Gross Unrealized Gains	1,121		2,257
Gross Unrealized Losses	(2,228)		(3,661)
Fair Value	169,219		195,117
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,395,669	[1]	2,443,282	[1]
Gross Unrealized Gains	12,306		9,718
Gross Unrealized Losses	(22,011)		(31,640)
Fair Value	2,385,964		2,421,360
Collateralized Mortgage Obligations Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	397,054	[1]	406,717	[1]
Gross Unrealized Gains	1,616		698
Gross Unrealized Losses	(4,761)		(8,875)
Fair Value	393,909		398,540
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,257	[1]	6,723	[1]
Gross Unrealized Gains	199		168
Gross Unrealized Losses	(2)		(2)
Fair Value	6,454		6,889
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,768	[1]	3,856	[1]
Gross Unrealized Gains	3,740		3,728
Gross Unrealized Losses	0		0
Fair Value	7,508		7,584
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,089	[1]	4,074	[1]
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(246)		(383)
Fair Value	$ 3,843		$ 3,691

[1] Amortized cost is adjusted for other-than-temporary impairment charges in 2014 and 2013, which have been recognized in the consolidated statements of income in the applicable year, and were considered inconsequential.