Investment Securities (Gross Unrealized Loss Table) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014 securities	Dec. 31, 2013 securities	Jun. 30, 2013 securities
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 472,977	$ 1,908,543	$ 1,633,108
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(5,046)	(67,758)	(46,766)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	55.000	218	220,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(1,418,752)	(199,691)	(51,138)
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(51,350)	(22,462)	(10,431)
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	161	46.000	8,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,891,729	2,108,234	1,684,246
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(56,396)	(90,220)	(57,197)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	187,242	2,373,148	2,191,336
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(1,434)	(118,026)	(68,866)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	64.000	492	485,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,747,578	2,478	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(67,419)	(183)	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	182	6.000	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,934,820	2,375,626	2,191,336
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(68,853)	(118,209)	(68,866)
US Government Agencies Debt Securities
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	23,652	23,807
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	(1,348)	(1,193)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	1	1,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	24,293	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(707)	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	1	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	24,293	23,652	23,807
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(707)	(1,348)	(1,193)
U.S. States and political subdivisions debt securities
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	10,988	38,039	61,933
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(16)	(1,996)	(3,527)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	14	65	106,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(30,271)	(14,157)	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(1,007)	(1,800)	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	50	25	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	41,259	52,196	61,933
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(1,023)	(3,796)	(3,527)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	59,958	222,154	228,098
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(334)	(10,276)	(9,041)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	56	353	362,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	66,557	2,478	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(919)	(183)	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	90	6	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	126,515	224,632	228,098
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(1,253)	(10,459)	(9,041)
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	11,636	434,761	331,857
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(3)	(13,109)	(10,192)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	1	35	23,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(259,470)	(14,890)	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(5,486)	(1,318)	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	19	2	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	271,106	449,651	331,857
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(5,489)	(14,427)	(10,192)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	422,192	225,681
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	(11,617)	(8,051)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	22	11,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	206,911	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(4,933)	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	11		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	206,911	422,192	225,681
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(4,933)	(11,617)	(8,051)
Commercial Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	5,105	33,387	51,378
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(4)	(1,491)	(2,141)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	1	5	7,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(45,739)	(16,944)	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(1,519)	(997)	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	6	2	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	50,844	50,331	51,378
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(1,523)	(2,488)	(2,141)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	48,831	39,697
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	(1,190)	(619)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	8	7,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	23,977	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(445)	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	3		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	23,977	48,831	39,697
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(445)	(1,190)	(619)
Residential Collateralized Mortgage-Backed Securities Issued by US Government Sponsored Enterprises
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	279,311	1,135,151	1,070,624
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(2,358)	(44,775)	(27,120)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	19	74	64,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(904,821)	(100,530)	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(32,491)	(7,293)	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	60	7	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,184,132	1,235,681	1,070,624
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(34,849)	(52,068)	(27,120)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	127,284	1,382,915	1,451,813
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(1,100)	(81,818)	(41,674)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	8	66	65,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,241,883	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(53,163)	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	60	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,369,167	1,382,915	1,451,813
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(54,263)	(81,818)	(41,674)
Residential Collateralized Mortgage-Backed Securities Issued by Non-US Government Agency
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	0
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(1)
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	0	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	0	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	0	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	0	0
Commercial Collateralized Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	24,431	43,747	42,537
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(97)	(2,055)	(1,965)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	1	6	6,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(43,212)	(2,525)	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(1,029)	(102)	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	6	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	67,643	46,272	42,537
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(1,126)	(2,157)	(1,965)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	208,863	150,223
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	(11,052)	(7,285)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	19	14,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	183,957	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(7,252)	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	17	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	183,957	208,863	150,223
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(7,252)	(11,052)	(7,285)
Collateralized Loan Obligations
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	141,506	223,458	74,779
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(2,568)	(4,332)	(1,821)
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	19	33	14,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(81,749)	0	0
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(1,684)	0	0
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	12	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	223,255	223,458	74,779
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(4,252)	(4,332)	(1,821)
Corporate debt securities
Securities available for sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	0	0
Available for Sale Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(53,490)	(50,644)	(51,138)
available for sale securities, continuous unrealized loss position, 12 months or longer, aggregate loss at end of period	(8,134)	(10,952)	(10,431)
Available for Sale Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	8	8	8,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	53,490	50,644	51,138
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss at End of Period	(8,134)	(10,952)	(10,431)
Securities held to maturity
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	64,541	72,017
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	(725)	(1,003)
Held to Maturity Securities in Unrealized Loss Positions Less than Twelve Months Qualitative Disclosure Number of Positions	0	23	25,000
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	0	0
Held to Maturity Securities in Unrealized Loss Positions Twelve Months or Longer Qualitative Disclosure Number of Positions	0	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	0	64,541	72,017
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 0	$ (725)	$ (1,003)