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Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | $ 24,171 | $ 17,689
Loans with a specific valuation allowance, Unpaid principal balance | 24,874 | 18,400
Specific valuation allowance | 4,468 | 5,223
Loans with a specific valuation allowance, Average balance | 20,931 | 18,986
Loans without a specific valuation allowance, Recorded balance | 114,373 | 102,305
Loans without a specific valuation allowance, Unpaid principal balance | 139,033 | 122,833
Loans without a specific valuation allowance, Average balance | 108,339 | 107,945
Recorded balance | 138,544 | 119,994
Unpaid principal balance | 163,907 | 141,233
Average balance | 129,270 | 126,931
Residential Real Estate | Residential Real Estate |  |
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | 3,627 | 2,978
Loans with a specific valuation allowance, Unpaid principal balance | 3,698 | 3,046
Specific valuation allowance | 167 | 246
Loans with a specific valuation allowance, Average balance | 3,303 | 2,928
Loans without a specific valuation allowance, Recorded balance | 9,630 | 9,421
Loans without a specific valuation allowance, Unpaid principal balance | 10,757 | 10,380
Loans without a specific valuation allowance, Average balance | 9,526 | 9,834
Recorded balance | 13,257 | 12,399
Unpaid principal balance | 14,455 | 13,426
Average balance | 12,829 | 12,762
Commercial | Commercial Real Estate |  |
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | 8,587 | 4,545
Loans with a specific valuation allowance, Unpaid principal balance | 8,787 | 4,573
Specific valuation allowance | 798 | 500
Loans with a specific valuation allowance, Average balance | 6,566 | 5,851
Loans without a specific valuation allowance, Recorded balance | 84,909 | 72,991
Loans without a specific valuation allowance, Unpaid principal balance | 104,008 | 89,839
Loans without a specific valuation allowance, Average balance | 78,950 | 76,427
Recorded balance | 93,496 | 77,536
Unpaid principal balance | 112,795 | 94,412
Average balance | 85,516 | 82,278
Commercial | Other Commercial |  |
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | 10,402 | 8,183
Loans with a specific valuation allowance, Unpaid principal balance | 10,404 | 8,378
Specific valuation allowance | 3,042 | 3,851
Loans with a specific valuation allowance, Average balance | 9,293 | 8,477
Loans without a specific valuation allowance, Recorded balance | 15,116 | 14,849
Loans without a specific valuation allowance, Unpaid principal balance | 18,934 | 16,931
Loans without a specific valuation allowance, Average balance | 14,982 | 15,129
Recorded balance | 25,518 | 23,032
Unpaid principal balance | 29,338 | 25,309
Average balance | 24,275 | 23,606
Consumer and Other | Home Equity |  |
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | 65 | 186
Loans with a specific valuation allowance, Unpaid principal balance | 79 | 199
Specific valuation allowance | 27 | 56
Loans with a specific valuation allowance, Average balance | 126 | 359
Loans without a specific valuation allowance, Recorded balance | 3,261 | 3,569
Loans without a specific valuation allowance, Unpaid principal balance | 3,795 | 4,098
Loans without a specific valuation allowance, Average balance | 3,415 | 4,734
Recorded balance | 3,326 | 3,755
Unpaid principal balance | 3,874 | 4,297
Average balance | 3,541 | 5,093
Consumer and Other | Other Consumer |  |
Summary of the impaired loans by portfolio class of loans |  |
Loans with a specific valuation allowance, Recorded balance | 1,490 | 1,797
Loans with a specific valuation allowance, Unpaid principal balance | 1,906 | 2,204
Specific valuation allowance | 434 | 570
Loans with a specific valuation allowance, Average balance | 1,643 | 1,371
Loans without a specific valuation allowance, Recorded balance | 1,457 | 1,475
Loans without a specific valuation allowance, Unpaid principal balance | 1,539 | 1,585
Loans without a specific valuation allowance, Average balance | 1,466 | 1,821
Recorded balance | 2,947 | 3,272
Unpaid principal balance | 3,445 | 3,789
Average balance | $ 3,109 | $ 3,192

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