Securities (Available for Sale Securities Losses) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value
Less than 12 months	$ 334,291	$ 1,034,016
12 months or longer	326,585	128,943
Total	660,876	1,162,959
Unrealized Losses
Less than 12 months	(7,412)	(30,517)
12 months or longer	(4,899)	(6,460)
Total	(12,311)	(36,977)
U.S. Government Corporations and Agencies
Fair Value
Less than 12 months	6,042	196,345
12 months or longer	0	0
Total	6,042	196,345
Unrealized Losses
Less than 12 months	(15)	(2,001)
12 months or longer	0	0
Total	(15)	(2,001)
Mortgage-Backed Securities
Fair Value
Less than 12 months	327,363	640,684
12 months or longer	306,078	118,229
Total	633,441	758,913
Unrealized Losses
Less than 12 months	(7,391)	(17,064)
12 months or longer	(4,577)	(5,510)
Total	(11,968)	(22,574)
Obligations of States and Political Subdivisions
Fair Value
Less than 12 months	886	196,987
12 months or longer	20,507	10,714
Total	21,393	207,701
Unrealized Losses
Less than 12 months	(6)	(11,452)
12 months or longer	(322)	(950)
Total	$ (328)	$ (12,402)

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.

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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.

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