Investment Securities (Schedule Of Unrealized Loss On Securities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	$ 841,842	$ 301,101
Securities Available-for-Sale, Less than 12 months, Unrealized losses	49,223	1,727
Securities Available-for-Sale, 12 months or longer, Fair value
Securities Available-for-Sale, 12 months or longer, Unrealized losses
Securities Available-for-Sale, Fair value, Total	841,842	301,101
Securities Available-for-Sale, Unrealized losses, Total	49,223	1,727
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	580,631	177,470
Securities Available-for-Sale, Less than 12 months, Unrealized losses	40,001	1,280
Securities Available-for-Sale, 12 months or longer, Fair value
Securities Available-for-Sale, 12 months or longer, Unrealized losses
Securities Available-for-Sale, Fair value, Total	580,631	177,470
Securities Available-for-Sale, Unrealized losses, Total	40,001	1,280
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	261,211	123,631
Securities Available-for-Sale, Less than 12 months, Unrealized losses	9,222	447
Securities Available-for-Sale, 12 months or longer, Fair value
Securities Available-for-Sale, 12 months or longer, Unrealized losses
Securities Available-for-Sale, Fair value, Total	261,211	123,631
Securities Available-for-Sale, Unrealized losses, Total	9,222	447
Securities Held-to-Maturity, Less than 12 months, Fair value	5,817	10,120
Securities Held-to-Maturity, Less than 12 months, Unrealized losses	15	38
Securities Held-to-Maturity, 12 months or longer, Fair value
Securities Held-to-Maturity, 12 months or longer, Unrealized losses
Securities Held-to-Maturity, Fair value, Total	5,817	10,120
Securities Held-to-Maturity, Unrealized losses, Total	$ 15	$ 38

Amount of unrealized loss on securities classified as available-for-sale that have been in a loss position for twelve months or longer.

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