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Allowance for Loan Losses - Investments in Loans Considered to be Impaired and Related Information on Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | $ 35 |  | $ 35 |  | $ 1,783
With a related allowance recorded, Unpaid Principal Balance | 35 |  | 35 |  | 1,835
Impaired financing receivable, Related Allowance | 35 |  | 35 |  | 77
Without a related allowance recorded, Recorded Investment | 33,730 |  | 33,730 |  | 25,040
Without a related allowance, Unpaid Principal Balance | 38,204 |  | 38,204 |  | 31,302
Impaired Financing Receivable, Recorded Investment, Total | 33,765 |  | 33,765 |  | 26,823
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 38,239 |  | 38,239 |  | 33,137
With a related allowance recorded, Average Recorded Investment | 38 | $ 863 | 25,092 | $ 39,203 |
With a related allowance recorded, Interest Income Recognized | 1 | 7 | 629 | 528 |
Without a related allowance recorded, Average Recorded Investment | 24,605 | 40,112 | 40 | 680 |
Without a related allowance recorded, Interest Income Recognized | 415 | 298 | 2 | 13 |
Impaired financing receivable, Average Recorded Investment, Total | 24,643 | 40,975 | 25,132 | 39,883 |
Impaired financing Receivable, Interest Income Recognized, Total | 416 | 305 | 631 | 541 |
Commercial real estate |  |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | 0 |  | 0 |  | 0
With a related allowance recorded, Unpaid Principal Balance | 0 |  | 0 |  | 0
Impaired financing receivable, Related Allowance | 0 |  | 0 |  | 0
Without a related allowance recorded, Recorded Investment | 3,555 |  | 3,555 |  | 3,546
Without a related allowance, Unpaid Principal Balance | 3,828 |  | 3,828 |  | 3,811
Impaired Financing Receivable, Recorded Investment, Total | 3,555 |  | 3,555 |  | 3,546
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 3,828 |  | 3,828 |  | 3,811
With a related allowance recorded, Average Recorded Investment | 0 | 0 | 3,712 | 7,028 |
With a related allowance recorded, Interest Income Recognized | 0 | 0 | 85 | 70 |
Without a related allowance recorded, Average Recorded Investment | 3,609 | 6,934 | 0 | 0 |
Without a related allowance recorded, Interest Income Recognized | 54 | 35 | 0 | 0 |
Impaired financing receivable, Average Recorded Investment, Total | 3,609 | 6,934 | 3,712 | 7,028 |
Impaired financing Receivable, Interest Income Recognized, Total | 54 | 35 | 85 | 70 |
Commercial and industrial |  |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | 0 |  | 0 |  | 1,735
With a related allowance recorded, Unpaid Principal Balance | 0 |  | 0 |  | 1,787
Impaired financing receivable, Related Allowance | 0 |  | 0 |  | 29
Without a related allowance recorded, Recorded Investment | 17,539 |  | 17,539 |  | 5,549
Without a related allowance, Unpaid Principal Balance | 19,281 |  | 19,281 |  | 7,980
Impaired Financing Receivable, Recorded Investment, Total | 17,539 |  | 17,539 |  | 7,284
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 19,281 |  | 19,281 |  | 9,767
With a related allowance recorded, Average Recorded Investment | 0 | 813 | 7,796 | 16,382 |
With a related allowance recorded, Interest Income Recognized | 0 | 6 | 218 | 124 |
Without a related allowance recorded, Average Recorded Investment | 8,060 | 17,625 | 0 | 628 |
Without a related allowance recorded, Interest Income Recognized | 210 | 95 | 0 | 11 |
Impaired financing receivable, Average Recorded Investment, Total | 8,060 | 18,438 | 7,796 | 17,010 |
Impaired financing Receivable, Interest Income Recognized, Total | 210 | 101 | 218 | 135 |
Commercial construction |  |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | 0 |  | 0 |  | 0
With a related allowance recorded, Unpaid Principal Balance | 0 |  | 0 |  | 0
Impaired financing receivable, Related Allowance | 0 |  | 0 |  | 0
Without a related allowance recorded, Recorded Investment | 3,441 |  | 3,441 |  | 5,464
Without a related allowance, Unpaid Principal Balance | 4,950 |  | 4,950 |  | 8,132
Impaired Financing Receivable, Recorded Investment, Total | 3,441 |  | 3,441 |  | 5,464
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 4,950 |  | 4,950 |  | 8,132
With a related allowance recorded, Average Recorded Investment | 0 | 0 | 3,445 | 4,267 |
With a related allowance recorded, Interest Income Recognized | 0 | 0 | 73 | 79 |
Without a related allowance recorded, Average Recorded Investment | 3,443 | 4,262 | 0 | 0 |
Without a related allowance recorded, Interest Income Recognized | 33 | 42 | 0 | 0 |
Impaired financing receivable, Average Recorded Investment, Total | 3,443 | 4,262 | 3,445 | 4,267 |
Impaired financing Receivable, Interest Income Recognized, Total | 33 | 42 | 73 | 79 |
Consumer real estate |  |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | 0 |  | 0 |  | 21
With a related allowance recorded, Unpaid Principal Balance | 0 |  | 0 |  | 21
Impaired financing receivable, Related Allowance | 0 |  | 0 |  | 21
Without a related allowance recorded, Recorded Investment | 9,186 |  | 9,186 |  | 10,467
Without a related allowance, Unpaid Principal Balance | 10,132 |  | 10,132 |  | 11,357
Impaired Financing Receivable, Recorded Investment, Total | 9,186 |  | 9,186 |  | 10,488
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 10,132 |  | 10,132 |  | 11,378
With a related allowance recorded, Average Recorded Investment | 0 | 24 | 10,128 | 11,514 |
With a related allowance recorded, Interest Income Recognized | 0 | 1 | 253 | 255 |
Without a related allowance recorded, Average Recorded Investment | 9,483 | 11,280 | 0 | 25 |
Without a related allowance recorded, Interest Income Recognized | 118 | 125 | 0 | 1 |
Impaired financing receivable, Average Recorded Investment, Total | 9,483 | 11,304 | 10,128 | 11,539 |
Impaired financing Receivable, Interest Income Recognized, Total | 118 | 126 | 253 | 256 |
Other consumer |  |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |  |
With a related allowance recorded, Recorded Investment | 35 |  | 35 |  | 27
With a related allowance recorded, Unpaid Principal Balance | 35 |  | 35 |  | 27
Impaired financing receivable, Related Allowance | 35 |  | 35 |  | 27
Without a related allowance recorded, Recorded Investment | 9 |  | 9 |  | 14
Without a related allowance, Unpaid Principal Balance | 13 |  | 13 |  | 22
Impaired Financing Receivable, Recorded Investment, Total | 44 |  | 44 |  | 41
Impaired Financing Receivable, Total Unpaid Principal Balance, Total | 48 |  | 48 |  | $ 49
With a related allowance recorded, Average Recorded Investment | 38 | 26 | 11 | 12 |
With a related allowance recorded, Interest Income Recognized | 1 | 0 | 0 | 0 |
Without a related allowance recorded, Average Recorded Investment | 10 | 11 | 40 | 27 |
Without a related allowance recorded, Interest Income Recognized | 0 | 1 | 2 | 1 |
Impaired financing receivable, Average Recorded Investment, Total | 48 | 37 | 51 | 39 |
Impaired financing Receivable, Interest Income Recognized, Total | $ 1 | $ 1 | $ 2 | $ 1 |

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