Investment Securities (Schedule Of Unrealized Loss On Investments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 1,866,812	$ 2,291,995
Less than 12 Months, Unrealized Losses	28,020	43,983
12 Months or Longer, Fair Value	49,358	4,713
12 Months or Longer, Unrealized Losses	1,228	578
Total Fair Value, Fair Value	1,916,170	2,296,708
Total Fair Value, Unrealized Losses	29,248	44,561
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Unrealized Losses	0	0
Total Fair Value, Fair Value	0	0
Total Fair Value, Unrealized Losses	0	0
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Unrealized Losses	0	0
Total Fair Value, Fair Value	0	0
Total Fair Value, Unrealized Losses	0	0
Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Unrealized Losses	0	0
Total Fair Value, Fair Value	0	0
Total Fair Value, Unrealized Losses	0	0
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	113,935	121,607
Less than 12 Months, Unrealized Losses	2,134	3,363
12 Months or Longer, Fair Value	1,116	2,951
12 Months or Longer, Unrealized Losses	94	298
Total Fair Value, Fair Value	115,051	124,558
Total Fair Value, Unrealized Losses	2,228	3,661
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,577,319	1,885,521
Less than 12 Months, Unrealized Losses	21,020	31,640
12 Months or Longer, Fair Value	46,342	0
12 Months or Longer, Unrealized Losses	991	0
Total Fair Value, Fair Value	1,623,661	1,885,521
Total Fair Value, Unrealized Losses	22,011	31,640
Collateralized Mortgage Obligations Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	173,574	282,898
Less than 12 Months, Unrealized Losses	4,761	8,875
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Unrealized Losses	0	0
Total Fair Value, Fair Value	173,574	282,898
Total Fair Value, Unrealized Losses	4,761	8,875
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	41	40
12 Months or Longer, Unrealized Losses	2	2
Total Fair Value, Fair Value	41	40
Total Fair Value, Unrealized Losses	2	2
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Unrealized Losses	0	0
Total Fair Value, Fair Value	0	0
Total Fair Value, Unrealized Losses	0	0
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,984	1,969
Less than 12 Months, Unrealized Losses	105	105
12 Months or Longer, Fair Value	1,859	1,722
12 Months or Longer, Unrealized Losses	141	278
Total Fair Value, Fair Value	3,843	3,691
Total Fair Value, Unrealized Losses	$ 246	$ 383