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Allowance for Loan Losses (the Allowance) - Allowance allocated by portfolio segment (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020 | Jun. 30, 2021 | Sep. 30, 2020 | Jun. 30, 2020 | Dec. 31, 2019
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases individually evaluated for impairment | $ 1,916 | $ 1,645 |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 17,060 | 16,122 |  |  |  |
Total | 18,976 | 17,767 | $ 18,361 | $ 16,573 | $ 12,706 | $ 9,513
Carrying value of loans and leases individually evaluated for impairment | 11,194 | 10,380 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 1,351,493 | 1,267,194 |  |  |  |
Total | 1,362,687 | 1,277,574 |  |  |  |
Commercial mortgage |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 6,542 | 7,451 |  |  |  |
Total | 6,542 | 7,451 | 7,146 | 6,935 | 5,277 | 3,426
Carrying value of loans and leases individually evaluated for impairment | 2,568 | 1,606 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 539,905 | 483,497 |  |  |  |
Total | 542,473 | 485,103 |  |  |  |
Home equity lines and loans |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases individually evaluated for impairment | 2 | 9 |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 271 | 425 |  |  |  |
Total | 273 | 434 | 281 | 517 | 672 | 342
Carrying value of loans and leases individually evaluated for impairment | 910 | 921 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 51,909 | 64,066 |  |  |  |
Total | 52,819 | 64,987 |  |  |  |
Residential mortgage |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases individually evaluated for impairment | 12 | 73 |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 264 | 312 |  |  |  |
Total | 276 | 385 | 324 | 334 | 346 | 179
Carrying value of loans and leases individually evaluated for impairment | 1,802 | 1,817 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 40,351 | 38,455 |  |  |  |
Total | 42,153 | 40,272 |  |  |  |
Construction |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 2,285 | 2,421 |  |  |  |
Total | 2,285 | 2,421 | 2,241 | 2,482 | 2,019 | 2,362
Carrying value of loans and leases individually evaluated for impairment | 1,206 | 1,206 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 160,986 | 139,040 |  |  |  |
Total | 162,192 | 140,246 |  |  |  |
Commercial and industrial |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases individually evaluated for impairment | 1,526 | 1,563 |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 4,088 | 3,868 |  |  |  |
Total | 5,614 | 5,431 | 5,360 | 5,038 | 3,606 | 2,684
Carrying value of loans and leases individually evaluated for impairment | 3,651 | 4,645 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 275,325 | 257,105 |  |  |  |
Total | 278,976 | 261,750 |  |  |  |
Small business loans |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases individually evaluated for impairment | 376 |  |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 2,723 | 1,259 |  |  |  |
Total | 3,099 | 1,259 | 2,235 | 1,107 | 747 | 509
Carrying value of loans and leases individually evaluated for impairment | 1,057 | 185 |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 89,420 | 49,357 |  |  |  |
Total | 90,477 | 49,542 |  |  |  |
Paycheck Protection Program loans ("PPP") |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 118,585 | 203,543 |  |  |  |
Total | 118,585 | 203,543 |  |  |  |
MainStreet Lending Program Loans ("PPP") |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Carrying value of loans and leases collectively evaluated for impairment | 592 | 580 |  |  |  |
Total | $ 592 | $ 580 |  |  |  |
Paycheck Protection Program And Main Street Lending Program Loans |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Percentage Guaranteed | 100.00% | 100.00% |  |  |  |
Consumer |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | $ 3 | $ 4 |  |  |  |
Total | 3 | 4 | 4 | 4 | 4 | 6
Carrying value of loans and leases collectively evaluated for impairment | 427 | 511 |  |  |  |
Total | 427 | 511 |  |  |  |
Leases, net |  |  |  |  |  |
Impaired Loans |  |  |  |  |  |
Allowance on loans and leases collectively evaluated for impairment | 884 | 382 |  |  |  |
Total | 884 | 382 | $ 770 | $ 156 | $ 35 | $ 5
Carrying value of loans and leases collectively evaluated for impairment | 73,993 | 31,040 |  |  |  |
Total | $ 73,993 | $ 31,040 |  |  |  |

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- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 + Details
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