Available-For-Sale And Held-To-Maturity Securities (Schedule Of Gross Unrealized Losses And The Estimated Fair Value By Length Of Time) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	$ (16,163)
Available-for-sale Securities, Estimated fair value, Less than 12 months	480,200
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(1,984)
Available-for-sale Securities, Estimated fair value, 12 months or more	76,551
Available-for-sale Securities, Gross unrealized losses, Total	(18,147)
Available-for-sale Securities, Estimated fair value, Total	556,751
U.S. Government Agency Securities [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(3)
Available-for-sale Securities, Estimated fair value, Less than 12 months	734
Available-for-sale Securities, Gross unrealized losses, Total	(3)
Available-for-sale Securities, Estimated fair value, Total	734
State And Municipal Securities [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(7,170)
Available-for-sale Securities, Estimated fair value, Less than 12 months	87,428
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(1,154)
Available-for-sale Securities, Estimated fair value, 12 months or more	32,096
Available-for-sale Securities, Gross unrealized losses, Total	(8,324)
Available-for-sale Securities, Estimated fair value, Total	119,524
Agency [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(2,067)
Available-for-sale Securities, Estimated fair value, Less than 12 months	83,099
Available-for-sale Securities, Gross unrealized losses, Total	(2,067)
Available-for-sale Securities, Estimated fair value, Total	83,099
Commercial [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(1,526)
Available-for-sale Securities, Estimated fair value, Less than 12 months	40,136
Available-for-sale Securities, Gross unrealized losses, Total	(1,526)
Available-for-sale Securities, Estimated fair value, Total	40,136
Corporate Fixed Income Securities [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(3,258)
Available-for-sale Securities, Estimated fair value, Less than 12 months	134,888
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(830)
Available-for-sale Securities, Estimated fair value, 12 months or more	44,455
Available-for-sale Securities, Gross unrealized losses, Total	(4,088)
Available-for-sale Securities, Estimated fair value, Total	179,343
Asset-Backed Securities [Member]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(2,139)
Available-for-sale Securities, Estimated fair value, Less than 12 months	133,915
Available-for-sale Securities, Gross unrealized losses, Total	(2,139)
Available-for-sale Securities, Estimated fair value, Total	$ 133,915