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Securities (Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses) (Details) - USD ($) $ in Thousands | Jun. 30, 2016 | Dec. 31, 2015
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Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | $ 44,694 | $ 18,352
Less than 12 Months Fair Value | 68,734 | 918,813
Less than 12 Months Unrealized Losses | (390) | (9,247)
12 Months or More Fair Value | 179,436 | 298,316
12 Months or More Unrealized Losses | (2,016) | (9,021)
Total Fair Value | 248,170 | 1,217,129
Total Unrealized Losses | (2,406) | (18,268)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 2,406 | 18,268
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 20,196 | 4,525
Less than 12 Months Fair Value | 51,222 | 664,509
Less than 12 Months Unrealized Losses | (264) | (7,610)
12 Months or More Fair Value | 170,543 | 214,325
12 Months or More Unrealized Losses | (1,837) | (7,381)
Total Fair Value | 221,765 | 878,834
Total Unrealized Losses | (2,101) | (14,991)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 2,101 | 14,991
State and Municipal Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 17,913 | 12,690
Less than 12 Months Fair Value | 17,512 | 48,261
Less than 12 Months Unrealized Losses | (126) | (358)
12 Months or More Fair Value | 6,077 | 31,383
12 Months or More Unrealized Losses | (40) | (580)
Total Fair Value | 23,589 | 79,644
Total Unrealized Losses | (166) | (938)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 166 | 938
US Government Corporations and Agencies Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 6,520 | 1,113
Less than 12 Months Fair Value |  | 193,400
Less than 12 Months Unrealized Losses |  | (1,128)
12 Months or More Fair Value |  | 40,034
12 Months or More Unrealized Losses |  | (718)
Total Fair Value |  | 233,434
Total Unrealized Losses |  | (1,846)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 0 | 1,846
US Government Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 1 | 0
Less than 12 Months Fair Value |  | 10,343
Less than 12 Months Unrealized Losses |  | (136)
12 Months or More Fair Value |  | 9,794
12 Months or More Unrealized Losses |  | (166)
Total Fair Value |  | 20,137
Total Unrealized Losses |  | (302)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 0 | 302
Other Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 64 | 24
Less than 12 Months Fair Value | 0 | 2,300
Less than 12 Months Unrealized Losses | 0 | (15)
12 Months or More Fair Value | 2,816 | 2,780
12 Months or More Unrealized Losses | (139) | (176)
Total Fair Value | 2,816 | 5,080
Total Unrealized Losses | (139) | (191)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | $ 139 | $ 191

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