Investment Securities (Summary Of Available For Sale Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 3,049,519	[1]	$ 3,224,749	[1]
Gross Unrealized Gains	24,828		19,170
Gross Unrealized Losses	(24,090)		(44,561)
Fair Value	3,050,257		3,199,358
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	42,627	[1]	17,791	[1]
Gross Unrealized Gains	41		0
Gross Unrealized Losses	0		0
Fair Value	42,668		17,791
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,435	[1]	33,480	[1]
Gross Unrealized Gains	1,034		1,161
Gross Unrealized Losses	0		0
Fair Value	27,469		34,641
Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	81,549	[1]	112,305	[1]
Gross Unrealized Gains	778		1,440
Gross Unrealized Losses	0		0
Fair Value	82,327		113,745
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	176,254	[1]	196,521	[1]
Gross Unrealized Gains	2,074		2,257
Gross Unrealized Losses	(933)		(3,661)
Fair Value	177,395		195,117
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,323,561	[1]	2,443,282	[1]
Gross Unrealized Gains	13,516		9,718
Gross Unrealized Losses	(20,469)		(31,640)
Fair Value	2,316,608		2,421,360
Collateralized Mortgage Obligations Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	371,656	[1]	406,717	[1]
Gross Unrealized Gains	4,052		698
Gross Unrealized Losses	(2,249)		(8,875)
Fair Value	373,459		398,540
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,099	[1]	6,723	[1]
Gross Unrealized Gains	204		168
Gross Unrealized Losses	(2)		(2)
Fair Value	5,301		6,889
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,228	[1]	3,856	[1]
Gross Unrealized Gains	3,129		3,728
Gross Unrealized Losses	0		0
Fair Value	6,357		7,584
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,110	[1]	4,074	[1]
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(437)		(383)
Fair Value	$ 18,673		$ 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.