Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 1,067,835	$ 1,099,658
Securities Available-for-Sale, Gross Unrealized Holdings Gains	9,554	16,523
Securities Available-for-Sale, Gross Unrealized Holding Losses	30,014	1,727
Securities Available-for-Sale, Total Fair value	1,047,375	1,114,454
Securities Held-to-Maturity, Amortized Cost	231,787	401,390
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	6,763	9,353
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	31	38
Securities Held-to-Maturity, Estimated Fair Value	238,519	410,705
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	620,640	695,655
Securities Available-for-Sale, Gross Unrealized Holdings Gains		1,352
Securities Available-for-Sale, Gross Unrealized Holding Losses	25,908	1,280
Securities Available-for-Sale, Total Fair value	594,732	695,727
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	804	984
Securities Available-for-Sale, Gross Unrealized Holdings Gains	5	19
Securities Available-for-Sale, Gross Unrealized Holding Losses
Securities Available-for-Sale, Total Fair value	809	1,003
Securities Held-to-Maturity, Amortized Cost	415	570
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	1	2
Securities Held-to-Maturity, Gross Unrecognized Holding Losses
Securities Held-to-Maturity, Estimated Fair Value	416	572
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	445,254	401,882
Securities Available-for-Sale, Gross Unrealized Holdings Gains	8,134	14,067
Securities Available-for-Sale, Gross Unrealized Holding Losses	4,106	447
Securities Available-for-Sale, Total Fair value	449,282	415,502
Securities Held-to-Maturity, Amortized Cost	231,372	400,820
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	6,762	9,351
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	31	38
Securities Held-to-Maturity, Estimated Fair Value	238,103	410,133
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,137	1,137
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1,415	1,085
Securities Available-for-Sale, Gross Unrealized Holding Losses
Securities Available-for-Sale, Total Fair value	$ 2,552	$ 2,222