Available-For-Sale And Held-To-Maturity Securities (Schedule Of Amortized Cost And Fair Values Of The Available For Sale Securities And Held To Maturity Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Available-for-sale Securities, Amortized cost	$ 1,762,516		$ 1,601,102
Available for sale securities, unrealized gains	14,022	[1]	27,460	[1]
Available-for-sale Securities, Gross unrealized losses	(20,285)	[1]	(3,394)	[1]
Available-for-sale securities, Estimated fair value	1,756,253		1,625,168
Held-to-maturity Securities, Amortized cost	1,312,115		708,008
Held-to-maturity Securities, Gross unrealized gains	7,324	[1]	10,776	[1]
Held-to-maturity Securities, Gross unrealized losses	(13,480)	[1]	(3,510)	[1]
Held-to-maturity securities, Estimated fair value	1,305,959		715,274
U.S. Government Agency Securities [Member]
Available-for-sale Securities, Amortized cost	1,074		1,114
Available for sale securities, unrealized gains		[1]	1	[1]
Available-for-sale Securities, Gross unrealized losses	(2)	[1]	(2)	[1]
Available-for-sale securities, Estimated fair value	1,072		1,113
State And Municipal Securities [Member]
Available-for-sale Securities, Amortized cost	96,475		153,885
Available for sale securities, unrealized gains	739	[1]	4,648	[1]
Available-for-sale Securities, Gross unrealized losses	(6,537)	[1]	(1,113)	[1]
Available-for-sale securities, Estimated fair value	90,677		157,420
Agency [Member]
Available-for-sale Securities, Amortized cost	184,533		676,861
Available for sale securities, unrealized gains	2,859	[1]	8,140	[1]
Available-for-sale Securities, Gross unrealized losses	(3,405)	[1]	(153)	[1]
Available-for-sale securities, Estimated fair value	183,987		684,848
Held-to-maturity Securities, Amortized cost	968,759
Held-to-maturity Securities, Gross unrealized gains	1,156	[1]
Held-to-maturity Securities, Gross unrealized losses	(7,915)	[1]
Held-to-maturity securities, Estimated fair value	962,000
Commercial [Member]
Available-for-sale Securities, Amortized cost	209,949		255,255
Available for sale securities, unrealized gains	3,084	[1]	5,902	[1]
Available-for-sale Securities, Gross unrealized losses	(1,787)	[1]	(183)	[1]
Available-for-sale securities, Estimated fair value	211,246		260,974
Held-to-maturity Securities, Amortized cost	59,404
Held-to-maturity Securities, Gross unrealized gains		[1]
Held-to-maturity Securities, Gross unrealized losses	(186)	[1]
Held-to-maturity securities, Estimated fair value	59,218
Non-Agency [Member]
Available-for-sale Securities, Amortized cost	4,547		13,077
Available for sale securities, unrealized gains	72	[1]	801	[1]
Available-for-sale Securities, Gross unrealized losses		[1]
Available-for-sale securities, Estimated fair value	4,619		13,878
Corporate Fixed Income Securities [Member]
Available-for-sale Securities, Amortized cost	496,385		474,338
Available for sale securities, unrealized gains	4,769	[1]	7,590	[1]
Available-for-sale Securities, Gross unrealized losses	(2,838)	[1]	(1,746)	[1]
Available-for-sale securities, Estimated fair value	498,316		480,182
Held-to-maturity Securities, Amortized cost	55,329		55,420
Held-to-maturity Securities, Gross unrealized gains	11	[1]	36	[1]
Held-to-maturity Securities, Gross unrealized losses	(2,605)	[1]	(519)	[1]
Held-to-maturity securities, Estimated fair value	52,735		54,937
Asset-Backed Securities [Member]
Available-for-sale Securities, Amortized cost	769,553		26,572
Available for sale securities, unrealized gains	2,499	[1]	378	[1]
Available-for-sale Securities, Gross unrealized losses	(5,716)	[1]	(197)	[1]
Available-for-sale securities, Estimated fair value	766,336		26,753
Held-to-maturity Securities, Amortized cost	228,623		630,279
Held-to-maturity Securities, Gross unrealized gains	6,157	[1]	9,364	[1]
Held-to-maturity Securities, Gross unrealized losses	(2,774)	[1]	(2,971)	[1]
Held-to-maturity securities, Estimated fair value	232,006		636,672
Municipal Auction Rate Securities [Member]
Held-to-maturity Securities, Amortized cost			22,309
Held-to-maturity Securities, Gross unrealized gains		[1]	1,376	[1]
Held-to-maturity Securities, Gross unrealized losses		[1]	(20)	[1]
Held-to-maturity securities, Estimated fair value			$ 23,665

[1] Unrealized gains/(losses) related to available-for-sale securities are reported in accumulated other comprehensive income.