Investment Securities (Amortized Cost And Estimated Fair Value Of Investments In Debt Securities By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Securities Available-for-Sale, Total Fair value	$ 1,197,295	$ 1,176,266
Securities Held-to-Maturity, Amortized Cost	162,304	182,061
Securities held-to-maturity, fair value	165,786	187,402
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Held-to-Maturity, Due within one year, Amortized cost	85
Securities Held-to-Maturity, Due within one year, Fair value	85
Held to Maturity Securities Debt Maturities Within One Year Weighted Avg Yield	4.40%
Securities Held-to-Maturity, Amortized Cost	85	240
Securities held-to-maturity, fair value	85	241
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Due one through five years, Amortized cost	173,750
Securities Available-for-Sale, Due one through five years, Fair value	167,842
Available for Sale Securities Debt Maturities After One Through Five Years Weighted Avg Yield	1.80%
Securities Available-for-Sale, Due five through ten years, Amortized cost	396,884
Securities Available-for-Sale, Due five through ten years, Fair value	384,094
Available for Sale Securities Debt Maturities After Five Through Ten Years Weighted Avg Yield	2.40%
Securities Available-for-Sale, Total, Amortized cost	570,634
Securities Available-for-Sale, Total Fair value	551,936	525,136
Available for Sale Securities Weighted Avg Yield	2.20%
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Total, Amortized cost	634,465
Securities Available-for-Sale, Total Fair value	642,710	648,471
Available for Sale Securities Weighted Avg Yield	2.50%
Securities Held-to-Maturity, Amortized Cost	162,219	181,821
Securities held-to-maturity, fair value	$ 165,701	$ 187,161
Held to Maturity Securities weighted avg yield	3.40%