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Investment Securities (Investments Gross Unrealized Losses And Fair Value) (Details) - USD ($) $ in Thousands | Mar. 31, 2017 | Dec. 31, 2016
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Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | $ 345,890 | $ 363,419
Securities available for sale, Less than 12 months, Unrealized Losses | 5,989 | 6,991
Securities available for sale, 12 months or longer, Fair Value | 2,520 | 1,458
Securities available for sale, 12 months or longer, Unrealized Losses | 21 | 3
Securities available for sale, Fair Value, Total | 348,410 | 364,877
Securities available for sale, Unrealized Losses, Total | 6,010 | 6,994
Securities held to maturity, Less than 12 months, Fair Value | 248,041 | 279,439
Securities held to maturity, Less than 12 months, Unrealized Losses | 4,780 | 5,618
Securities held to maturity, 12 months or longer, Fair Value | 3,677 | 4,068
Securities held to maturity, 12 months or longer, Unrealized Losses | 16 | 16
Securities held to maturity, Fair Value, Total | 251,718 | 283,507
Securities held to maturity, Unrealized Losses, Total | 4,796 | 5,634
Total Securities, Less than 12 months, Fair Value | 593,931 | 642,858
Total Securities, Less than 12 months, Unrealized Losses | 10,769 | 12,609
Total Securities, 12 months or longer, Fair Value | 6,197 | 5,526
Total Securities, 12 months or longer, Unrealized Losses | 37 | 19
Total Securities, Fair Value | 600,128 | 648,384
Total Securities, Unrealized Losses | 10,806 | 12,628
U.S. Government Agencies And Government Sponsored Enterprises [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 96,026 | 113,261
Securities available for sale, Less than 12 months, Unrealized Losses | 1,171 | 1,566
Securities available for sale, 12 months or longer, Fair Value | 1,412 | 1,458
Securities available for sale, 12 months or longer, Unrealized Losses | 2 | 3
Securities available for sale, Fair Value, Total | 97,438 | 114,719
Securities available for sale, Unrealized Losses, Total | 1,173 | 1,569
State And Political Subdivisions [Member] |  |
Investment [Line Items] |  |
Securities held to maturity, Less than 12 months, Fair Value | 47,118 | 82,644
Securities held to maturity, Less than 12 months, Unrealized Losses | 892 | 1,616
Securities held to maturity, Fair Value, Total | 47,118 | 82,644
Securities held to maturity, Unrealized Losses, Total | 892 | 1,616
Collateralized Mortgage Obligations [Member] | Federal National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 252 | 8,119
Securities available for sale, Less than 12 months, Unrealized Losses | 1 | 125
Securities available for sale, 12 months or longer, Fair Value | 55 |
Securities available for sale, 12 months or longer, Unrealized Losses | 1 |
Securities available for sale, Fair Value, Total | 307 | 8,119
Securities available for sale, Unrealized Losses, Total | 2 | 125
Securities held to maturity, Less than 12 months, Fair Value | 67,013 | 72,734
Securities held to maturity, Less than 12 months, Unrealized Losses | 1,420 | 1,560
Securities held to maturity, 12 months or longer, Fair Value | 2,700 | 3,107
Securities held to maturity, 12 months or longer, Unrealized Losses | 13 | 13
Securities held to maturity, Fair Value, Total | 69,713 | 75,841
Securities held to maturity, Unrealized Losses, Total | 1,433 | 1,573
Collateralized Mortgage Obligations [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 59 | 5,077
Securities available for sale, Less than 12 months, Unrealized Losses | 1 | 65
Securities available for sale, Fair Value, Total | 59 | 5,077
Securities available for sale, Unrealized Losses, Total | 1 | 65
Securities held to maturity, Less than 12 months, Fair Value | 87,601 | 92,256
Securities held to maturity, Less than 12 months, Unrealized Losses | 1,789 | 1,825
Securities held to maturity, 12 months or longer, Fair Value | 672 | 430
Securities held to maturity, 12 months or longer, Unrealized Losses | 2 | 2
Securities held to maturity, Fair Value, Total | 88,273 | 92,686
Securities held to maturity, Unrealized Losses, Total | 1,791 | 1,827
Collateralized Mortgage Obligations [Member] | Government National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities held to maturity, Less than 12 months, Fair Value | 8,042 | 8,675
Securities held to maturity, Less than 12 months, Unrealized Losses | 148 | 161
Securities held to maturity, 12 months or longer, Fair Value | 305 | 531
Securities held to maturity, 12 months or longer, Unrealized Losses | 1 | 1
Securities held to maturity, Fair Value, Total | 8,347 | 9,206
Securities held to maturity, Unrealized Losses, Total | 149 | 162
Mortgage-Backed Securities [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 249,864 | 250,158
Securities available for sale, Less than 12 months, Unrealized Losses | 4,818 | 5,425
Securities available for sale, 12 months or longer, Fair Value | 1,108 |
Securities available for sale, 12 months or longer, Unrealized Losses | 19 |
Securities available for sale, Fair Value, Total | 250,972 | 250,158
Securities available for sale, Unrealized Losses, Total | 4,837 | 5,425
Securities held to maturity, Less than 12 months, Fair Value | 200,923 | 196,795
Securities held to maturity, Less than 12 months, Unrealized Losses | 3,888 | 4,002
Securities held to maturity, 12 months or longer, Fair Value | 3,677 | 4,068
Securities held to maturity, 12 months or longer, Unrealized Losses | 16 | 16
Securities held to maturity, Fair Value, Total | 204,600 | 200,863
Securities held to maturity, Unrealized Losses, Total | 3,904 | 4,018
Mortgage-Backed Securities [Member] | Federal National Mortgage Association [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 220,754 | 211,491
Securities available for sale, Less than 12 months, Unrealized Losses | 4,008 | 4,413
Securities available for sale, Fair Value, Total | 220,754 | 211,491
Securities available for sale, Unrealized Losses, Total | 4,008 | 4,413
Securities held to maturity, Less than 12 months, Fair Value | 10,169 | 9,253
Securities held to maturity, Less than 12 months, Unrealized Losses | 121 | 124
Securities held to maturity, Fair Value, Total | 10,169 | 9,253
Securities held to maturity, Unrealized Losses, Total | 121 | 124
Mortgage-Backed Securities [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Investment [Line Items] |  |
Securities available for sale, Less than 12 months, Fair Value | 28,799 | 24,360
Securities available for sale, Less than 12 months, Unrealized Losses | 808 | 807
Securities available for sale, Fair Value, Total | 28,799 | 24,360
Securities available for sale, Unrealized Losses, Total | 808 | 807
Securities held to maturity, Less than 12 months, Fair Value | 3,116 | 3,141
Securities held to maturity, Less than 12 months, Unrealized Losses | 154 | 150
Securities held to maturity, Fair Value, Total | 3,116 | 3,141
Securities held to maturity, Unrealized Losses, Total | 154 | 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
Securities available for sale, Less than 12 months, Unrealized Losses |  | 15
Securities available for sale, 12 months or longer, Fair Value | 1,053 |
Securities available for sale, 12 months or longer, Unrealized Losses | 18 |
Securities available for sale, Fair Value, Total | 1,053 | 1,111
Securities available for sale, Unrealized Losses, Total | 18 | 15
Securities held to maturity, Less than 12 months, Fair Value | 24,982 | 10,736
Securities held to maturity, Less than 12 months, Unrealized Losses | 256 | 182
Securities held to maturity, Fair Value, Total | 24,982 | 10,736
Securities held to maturity, Unrealized Losses, Total | $ 256 | $ 182

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