Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Less than 12 months, Fair Value	$ 1,032,967	$ 2,125,723
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,281	5,488
12 months or longer, Fair Value	882,959	1,137,135
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	18,446	29,896
Total, Fair Value	1,915,926	3,262,858
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	19,727	35,384
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	0	90,261
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	818
12 months or longer, Fair Value	32,641	32,077
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,925	4,206
Total, Fair Value	32,641	122,338
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2,925	5,024
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	11,439	224,808
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	35	922
12 months or longer, Fair Value	159,458	224,779
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,066	7,118
Total, Fair Value	170,897	449,587
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3,101	8,040
State And Municipal Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	81,475	172,980
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	315	646
12 months or longer, Fair Value	125,284	215,702
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	6,297	7,708
Total, Fair Value	206,759	388,682
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,612	8,354
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	33,319	55,128
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	35	429
12 months or longer, Fair Value	323,023	381,617
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,681	5,163
Total, Fair Value	356,342	436,745
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3,716	5,592
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	29,873	141,655
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	47	609
12 months or longer, Fair Value	43,981	43,659
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	231	619
Total, Fair Value	73,854	185,314
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	278	1,228
Asset-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	852,860	1,424,457
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	801	2,009
12 months or longer, Fair Value	157,377	159,098
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,808	3,094
Total, Fair Value	1,010,237	1,583,555
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2,609	5,103
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	916,052	1,621,240
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	883	3,047
12 months or longer, Fair Value	524,381	584,374
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	5,720	8,876
Total, Fair Value	1,440,433	2,205,614
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,603	11,923
Debt Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	24,001	16,434
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	48	55
12 months or longer, Fair Value	41,195	80,203
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	438	1,988
Total, Fair Value	65,196	96,637
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 486	$ 2,043

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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-Section 50

-Paragraph 6

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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