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Investment Securities (Investments' Gross Unrealized Losses And Fair Value) (Details) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
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Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | $ 363,419 | $ 232,913
Securities available for sale, Less than 12 months, Unrealized Losses | 6,991 | 3,312
Securities available for sale, 12 months or longer, Fair Value | 1,458 | 35,864
Securities available for sale, 12 months or longer, Unrealized Losses | 3 | 513
Securities available for sale, Fair Value, Total | 364,877 | 268,777
Securities available for sale, Unrealized Losses, Total | 6,994 | 3,825
Securities held to maturity, Less than 12 months, Fair Value | 279,439 | 167,386
Securities held to maturity, Less than 12 months, Unrealized Losses | 5,618 | 2,281
Securities held to maturity, 12 months or longer, Fair Value | 4,068 |
Securities held to maturity, 12 months or longer, Unrealized Losses | 16 |
Securities held to maturity, Fair Value, Total | 283,507 | 167,386
Securities held to maturity, Unrealized Losses, Total | 5,634 | 2,281
Total Securities, Less than 12 months, Fair Value | 642,858 | 400,299
Total Securities, Less than 12 months, Unrealized Losses | 12,609 | 5,593
Total Securities, 12 months or longer, Fair Value | 5,526 | 35,864
Total Securities, 12 months or longer, Unrealized Losses | 19 | 513
Total Securities, Fair Value | 648,384 | 436,163
Total Securities, Unrealized Losses | 12,628 | 6,106
U.S. Government Agencies And Government Sponsored Enterprises [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 113,261 | 82,298
Securities available for sale, Less than 12 months, Unrealized Losses | 1,566 | 735
Securities available for sale, 12 months or longer, Fair Value | 1,458 | 26,302
Securities available for sale, 12 months or longer, Unrealized Losses | 3 | 314
Securities available for sale, Fair Value, Total | 114,719 | 108,600
Securities available for sale, Unrealized Losses, Total | 1,569 | 1,049
State And Political Subdivisions [Member] |  |
Investment [Line Items] |  |
Securities held to maturity, Less than 12 months, Fair Value | 82,644 | 3,075
Securities held to maturity, Less than 12 months, Unrealized Losses | 1,616 | 4
Securities held to maturity, Fair Value, Total | 82,644 | 3,075
Securities held to maturity, Unrealized Losses, Total | 1,616 | 4
Collateralized Mortgage Obligations [Member] | Federal National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 8,119 | 7,778
Securities available for sale, Less than 12 months, Unrealized Losses | 125 | 154
Securities available for sale, Fair Value, Total | 8,119 | 7,778
Securities available for sale, Unrealized Losses, Total | 125 | 154
Securities held to maturity, Less than 12 months, Fair Value | 72,734 | 55,973
Securities held to maturity, Less than 12 months, Unrealized Losses | 1,560 | 818
Securities held to maturity, 12 months or longer, Fair Value | 3,107 |
Securities held to maturity, 12 months or longer, Unrealized Losses | 13 |
Securities held to maturity, Fair Value, Total | 75,841 | 55,973
Securities held to maturity, Unrealized Losses, Total | 1,573 | 818
Collateralized Mortgage Obligations [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 5,077 | 4,998
Securities available for sale, Less than 12 months, Unrealized Losses | 65 | 91
Securities available for sale, Fair Value, Total | 5,077 | 4,998
Securities available for sale, Unrealized Losses, Total | 65 | 91
Securities held to maturity, Less than 12 months, Fair Value | 92,256 | 79,323
Securities held to maturity, Less than 12 months, Unrealized Losses | 1,825 | 1,120
Securities held to maturity, 12 months or longer, Fair Value | 430 |
Securities held to maturity, 12 months or longer, Unrealized Losses | 2 |
Securities held to maturity, Fair Value, Total | 92,686 | 79,323
Securities held to maturity, Unrealized Losses, Total | 1,827 | 1,120
Collateralized Mortgage Obligations [Member] | Government National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities held to maturity, Less than 12 months, Fair Value | 8,675 | 14,559
Securities held to maturity, Less than 12 months, Unrealized Losses | 161 | 101
Securities held to maturity, 12 months or longer, Fair Value | 531 |
Securities held to maturity, 12 months or longer, Unrealized Losses | 1 |
Securities held to maturity, Fair Value, Total | 9,206 | 14,559
Securities held to maturity, Unrealized Losses, Total | 162 | 101
Mortgage-Backed Securities [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 250,158 | 150,615
Securities available for sale, Less than 12 months, Unrealized Losses | 5,425 | 2,577
Securities available for sale, 12 months or longer, Fair Value |  | 9,562
Securities available for sale, 12 months or longer, Unrealized Losses |  | 199
Securities available for sale, Fair Value, Total | 250,158 | 160,177
Securities available for sale, Unrealized Losses, Total | 5,425 | 2,776
Securities held to maturity, Less than 12 months, Fair Value | 196,795 | 164,311
Securities held to maturity, Less than 12 months, Unrealized Losses | 4,002 | 2,277
Securities held to maturity, 12 months or longer, Fair Value | 4,068 |
Securities held to maturity, 12 months or longer, Unrealized Losses | 16 |
Securities held to maturity, Fair Value, Total | 200,863 | 164,311
Securities held to maturity, Unrealized Losses, Total | 4,018 | 2,277
Mortgage-Backed Securities [Member] | Federal National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 211,491 | 123,774
Securities available for sale, Less than 12 months, Unrealized Losses | 4,413 | 2,134
Securities available for sale, 12 months or longer, Fair Value |  | 9,562
Securities available for sale, 12 months or longer, Unrealized Losses |  | 199
Securities available for sale, Fair Value, Total | 211,491 | 133,336
Securities available for sale, Unrealized Losses, Total | 4,413 | 2,333
Securities held to maturity, Less than 12 months, Fair Value | 9,253 | 5,666
Securities held to maturity, Less than 12 months, Unrealized Losses | 124 | 79
Securities held to maturity, Fair Value, Total | 9,253 | 5,666
Securities held to maturity, Unrealized Losses, Total | 124 | 79
Mortgage-Backed Securities [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 24,360 | 12,660
Securities available for sale, Less than 12 months, Unrealized Losses | 807 | 194
Securities available for sale, Fair Value, Total | 24,360 | 12,660
Securities available for sale, Unrealized Losses, Total | 807 | 194
Securities held to maturity, Less than 12 months, Fair Value | 3,141 |
Securities held to maturity, Less than 12 months, Unrealized Losses | 150 |
Securities held to maturity, Fair Value, Total | 3,141 |
Securities held to maturity, Unrealized Losses, Total | 150 |
Mortgage-Backed Securities [Member] | Government National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 1,111 | 1,405
Securities available for sale, Less than 12 months, Unrealized Losses | 15 | 4
Securities available for sale, Fair Value, Total | 1,111 | 1,405
Securities available for sale, Unrealized Losses, Total | 15 | 4
Securities held to maturity, Less than 12 months, Fair Value | 10,736 | 8,790
Securities held to maturity, Less than 12 months, Unrealized Losses | 182 | 159
Securities held to maturity, Fair Value, Total | 10,736 | 8,790
Securities held to maturity, Unrealized Losses, Total | $ 182 | $ 159

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