Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investment [Line Items]
Less than 12 months, Fair Value	$ 486,183	$ 3,012,123
Less than 12 months, Unrealized Losses	1,149	75,636
12 months or longer, Fair Value	1,508,542	421,202
12 months or longer, Unrealized Losses	45,620	42,542
Total, Fair Value	1,994,725	3,433,325
Total, Unrealized Losses	46,769	118,178
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	0	96,172
Less than 12 months, Unrealized Losses	0	243
12 months or longer, Fair Value	32,570	59,677
12 months or longer, Unrealized Losses	3,965	12,901
Total, Fair Value	32,570	155,849
Total, Unrealized Losses	3,965	13,144
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	69,973	487,317
Less than 12 months, Unrealized Losses	102	18,155
12 months or longer, Fair Value	295,532	93,654
12 months or longer, Unrealized Losses	12,225	9,126
Total, Fair Value	365,505	580,971
Total, Unrealized Losses	12,327	27,281
State And Municipal Obligations [Member]
Investment [Line Items]
Less than 12 months, Fair Value	131,531	478,818
Less than 12 months, Unrealized Losses	711	15,520
12 months or longer, Fair Value	355,533	178,150
12 months or longer, Unrealized Losses	12,112	17,825
Total, Fair Value	487,064	656,968
Total, Unrealized Losses	12,823	33,345
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	4,775	717,778
Less than 12 months, Unrealized Losses	16	26,124
12 months or longer, Fair Value	400,697	0
12 months or longer, Unrealized Losses	10,089	0
Total, Fair Value	405,472	717,778
Total, Unrealized Losses	10,105	26,124
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	37,014	53,454
Less than 12 months, Unrealized Losses	23	918
12 months or longer, Fair Value	43,762	22,289
12 months or longer, Unrealized Losses	644	702
Total, Fair Value	80,776	75,743
Total, Unrealized Losses	667	1,620
Asset-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	236,398	1,088,556
Less than 12 months, Unrealized Losses	294	9,072
12 months or longer, Fair Value	296,606	58,398
12 months or longer, Unrealized Losses	4,115	1,097
Total, Fair Value	533,004	1,146,954
Total, Unrealized Losses	4,409	10,169
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	278,187	1,859,788
Less than 12 months, Unrealized Losses	333	36,114
12 months or longer, Fair Value	741,065	80,687
12 months or longer, Unrealized Losses	14,848	1,799
Total, Fair Value	1,019,252	1,940,475
Total, Unrealized Losses	15,181	37,913
Debt Securities [Member]
Investment [Line Items]
Less than 12 months, Fair Value	6,492	90,028
Less than 12 months, Unrealized Losses	3	5,604
12 months or longer, Fair Value	83,842	9,034
12 months or longer, Unrealized Losses	2,470	891
Total, Fair Value	90,334	99,062
Total, Unrealized Losses	$ 2,473	$ 6,495