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Securities (Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses) (Details) - USD ($) $ in Thousands | Sep. 30, 2015 | Dec. 31, 2014
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Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | $ 29,138 | $ 25,527
Less than 12 Months Fair Value | 162,400 | 437,414
Less than 12 Months Unrealized Losses | (966) | (2,350)
12 Months or More Fair Value | 301,749 | 561,668
12 Months or More Unrealized Losses | (5,476) | (11,989)
Total Fair Value | 464,149 | 999,082
Total Unrealized Losses | (6,442) | (14,339)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 6,442 | 14,339
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 | 12,610 | 10,219
Less than 12 Months Fair Value | 124,092 | 258,825
Less than 12 Months Unrealized Losses | (804) | (1,287)
12 Months or More Fair Value | 204,165 | 279,015
12 Months or More Unrealized Losses | (4,328) | (6,924)
Total Fair Value | 328,257 | 537,840
Total Unrealized Losses | (5,132) | (8,211)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 5,132 | 8,210
State and Municipal Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 13,574 | 14,432
Less than 12 Months Fair Value | 37,808 | 71,026
Less than 12 Months Unrealized Losses | (161) | (543)
12 Months or More Fair Value | 29,960 | 44,148
12 Months or More Unrealized Losses | (594) | (982)
Total Fair Value | 67,768 | 115,174
Total Unrealized Losses | (755) | (1,525)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 755 | 1,526
US Government Corporations and Agencies Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 2,922 | 856
Less than 12 Months Fair Value | 500 | 105,250
Less than 12 Months Unrealized Losses | (1) | (518)
12 Months or More Fair Value | 54,892 | 216,221
12 Months or More Unrealized Losses | (374) | (3,551)
Total Fair Value | 55,392 | 321,471
Total Unrealized Losses | (375) | (4,069)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 375 | 4,069
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 | 0 | 0
Less than 12 Months Unrealized Losses | 0 | 0
12 Months or More Fair Value | 9,925 | 19,450
12 Months or More Unrealized Losses | (32) | (411)
Total Fair Value | 9,925 | 19,450
Total Unrealized Losses | (32) | (411)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 32 | 411
Other Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale Debt Securities Gross Unrealized Gain, instant | 31 | 20
Less than 12 Months Fair Value | 0 | 2,313
Less than 12 Months Unrealized Losses | 0 | (2)
12 Months or More Fair Value | 2,807 | 2,834
12 Months or More Unrealized Losses | (148) | (121)
Total Fair Value | 2,807 | 5,147
Total Unrealized Losses | (148) | (123)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | $ 148 | $ 123

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