Investment Securities Available for Sale (Summary Of Available For Sale Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 3,224,749	$ 2,931,630
Gross Unrealized Gains	19,170	54,116
Gross Unrealized Losses	(44,561)	(4,634)
Fair Value	3,199,358	2,981,112
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,791	356
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	17,791	356
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,480	35,791
Gross Unrealized Gains	1,161	2,255
Gross Unrealized Losses	0	0
Fair Value	34,641	38,046
Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	112,305	289,523
Gross Unrealized Gains	1,440	3,787
Gross Unrealized Losses	0	0
Fair Value	113,745	293,310
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	196,521	238,381
Gross Unrealized Gains	2,257	7,220
Gross Unrealized Losses	(3,661)	(8)
Fair Value	195,117	245,593
Mortgage-Backed Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,443,282	1,832,076
Gross Unrealized Gains	9,718	37,646
Gross Unrealized Losses	(31,640)	(2,229)
Fair Value	2,421,360	1,867,493
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	406,717	513,637
Gross Unrealized Gains	698	2,534
Gross Unrealized Losses	(8,875)	(1,682)
Fair Value	398,540	514,489
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,723	15,218
Gross Unrealized Gains	168	582
Gross Unrealized Losses	(2)	(2)
Fair Value	6,889	15,798
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,856	3,648
Gross Unrealized Gains	3,728	92
Gross Unrealized Losses	0	0
Fair Value	7,584	3,740
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,074	3,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(383)	(713)
Fair Value	$ 3,691	$ 2,287