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Goodwill (Tables) | 3 Months Ended
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Mar. 31, 2020
Goodwill |
Schedule of changes in the carrying amount of goodwill | The changes in the carrying amount of goodwill are as follows (in thousands): ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Mechanical Services | ​ | Electrical Services | ​ | ​
​ |  | Segment |  | Segment | ​ | Total
Balance at December 31, 2018 | ​ | $ | 235,182 | ​ | $ | — | ​ | $ | 235,182
Acquisitions and purchase price adjustments (See Note 4) | ​ |  | 579 | ​ |  | 96,686 | ​ | ​ | 97,265
Impact of segment reorganization | ​ | ​ | (1,101) | ​ | ​ | 1,101 | ​ | ​ | —
Balance at December 31, 2019 | ​ | ​ | 234,660 | ​ | ​ | 97,787 | ​ | ​ | 332,447
Acquisitions and purchase price adjustments (See Note 4) | ​ | ​ | — | ​ | ​ | 14,944 | ​ | ​ | 14,944
Balance at March 31, 2020 | ​ | $ | 234,660 | ​ | $ | 112,731 | ​ | $ | 347,391

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- Definition Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267 + Details
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