Securities (Continuous Unrealized-Loss Position of Available-For-Sale And Held-To-Maturity Securities) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Fair Value	$ 52,362	$ 275,028
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	1,012	7,545
Available-for-sale and held-to-maturity securities, continuous unrealized loss position 12 Months or Longer, Fair Value	1,748	2,070
Available-for-sale and held-to-maturity securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss	22	196
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Fair Value	54,110	277,098
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Unrealized Loss	1,034	7,741
Obligations Of States And Political Subdivisions [Member]
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Fair Value	24,290	164,437
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	467	5,665
Available-for-sale and held-to-maturity securities, continuous unrealized loss position 12 Months or Longer, Fair Value	1,748	2,070
Available-for-sale and held-to-maturity securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss	22	196
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Fair Value	26,038	166,507
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Unrealized Loss	489	5,861
Mortgage-Backed Securities [Member]
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Fair Value	28,072	110,591
Available-for-sale and held-to-maturity securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	545	1,880
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Fair Value	28,072	110,591
Available-for-sale and held-to-maturity securities, continuous unrealized loss position, Unrealized Loss	$ 545	$ 1,880