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	Sep. 30, 2012		Dec. 31, 2011
Available-for-sale Securities, Amortized cost	$ 1,446,097		$ 1,204,205
Available-for-sale Securities, Gross unrealized gains	33,388	[1]	18,050	[1]
Available-for-sale Securities, Gross unrealized losses	(2,804)	[1]	(8,114)	[1]
Available-for-sale securities, Estimated fair value	1,476,681		1,214,141
Held-to-maturity Securities, Amortized cost	657,933	[2]	190,484	[2]
Held-to-maturity Securities, Gross unrealized gains	11,116	[1],[2]	3,742	[1],[2]
Held-to-maturity Securities, Gross unrealized losses	(4,456)	[1],[2]	(5,155)	[1],[2]
Held-to-maturity securities, Estimated fair value	664,593	[2]	189,071	[2]
U.S. Government Agency Securities [Member]
Available-for-sale Securities, Amortized cost	1,115		1,105
Available-for-sale Securities, Gross unrealized gains		[1]
Available-for-sale Securities, Gross unrealized losses		[1]	(2)	[1]
Available-for-sale securities, Estimated fair value	1,115		1,103
State And Municipal Securities [Member]
Available-for-sale Securities, Amortized cost	137,257		82,256
Available-for-sale Securities, Gross unrealized gains	5,912	[1]	4,979	[1]
Available-for-sale Securities, Gross unrealized losses	(583)	[1]	(303)	[1]
Available-for-sale securities, Estimated fair value	142,586		86,932
Agency [Member]
Available-for-sale Securities, Amortized cost	507,897		396,952
Available-for-sale Securities, Gross unrealized gains	12,435	[1]	8,469	[1]
Available-for-sale Securities, Gross unrealized losses		[1]	(759)	[1]
Available-for-sale securities, Estimated fair value	520,332		404,662
Commercial [Member]
Available-for-sale Securities, Amortized cost	264,417		270,677
Available-for-sale Securities, Gross unrealized gains	5,878	[1]	1,811	[1]
Available-for-sale Securities, Gross unrealized losses	(487)	[1]	(978)	[1]
Available-for-sale securities, Estimated fair value	269,808		271,510
Non-Agency [Member]
Available-for-sale Securities, Amortized cost	14,093		17,701
Available-for-sale Securities, Gross unrealized gains	672	[1]	135	[1]
Available-for-sale Securities, Gross unrealized losses		[1]	(376)	[1]
Available-for-sale securities, Estimated fair value	14,765		17,460
Corporate Fixed Income Securities [Member]
Available-for-sale Securities, Amortized cost	494,451		409,503
Available-for-sale Securities, Gross unrealized gains	8,031	[1]	2,108	[1]
Available-for-sale Securities, Gross unrealized losses	(1,500)	[1]	(5,626)	[1]
Available-for-sale securities, Estimated fair value	500,982		405,985
Held-to-maturity Securities, Amortized cost	55,443	[2]	55,544	[2]
Held-to-maturity Securities, Gross unrealized gains	174	[1],[2]	56	[1],[2]
Held-to-maturity Securities, Gross unrealized losses	(1,150)	[1],[2]	(2,016)	[1],[2]
Held-to-maturity securities, Estimated fair value	54,467	[2]	53,584	[2]
Asset-Backed Securities [Member]
Available-for-sale Securities, Amortized cost	26,867		26,011
Available-for-sale Securities, Gross unrealized gains	460	[1]	548	[1]
Available-for-sale Securities, Gross unrealized losses	(234)	[1]	(70)	[1]
Available-for-sale securities, Estimated fair value	27,093		26,489
Held-to-maturity Securities, Amortized cost	580,165	[2]	122,148	[2]
Held-to-maturity Securities, Gross unrealized gains	9,449	[1],[2]	2,953	[1],[2]
Held-to-maturity Securities, Gross unrealized losses	(3,290)	[1],[2]	(3,138)	[1],[2]
Held-to-maturity securities, Estimated fair value	586,324	[2]	121,963	[2]
Municipal Auction Rate Securities [Member]
Held-to-maturity Securities, Amortized cost	22,325	[2]	12,792	[2]
Held-to-maturity Securities, Gross unrealized gains	1,493	[1],[2]	733	[1],[2]
Held-to-maturity Securities, Gross unrealized losses	(16)	[1],[2]	(1)	[1],[2]
Held-to-maturity securities, Estimated fair value	$ 23,802	[2]	$ 13,524	[2]

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

[2] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.