Acquisitions Of Businesses	12 Months Ended
Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions Of Businesses	ACQUISITIONS OF BUSINESSES On January 4, 2017, March 1, 2017 and November 1, 2017, we acquired three companies for a total consideration of $109.3 million. One company provides fire protection and alarm services primarily in the Southern region of the United States. The second company provides millwright services for manufacturing companies throughout the United States. Both of their results have been included in our United States mechanical construction and facilities services segment. The third company provides mobile mechanical services within the Western region of the United States, and its results have been included in our United States building services segment. In connection with these acquisitions, we acquired working capital of $9.8 million and other net assets of $2.3 million and have preliminarily ascribed $40.6 million to goodwill and $56.6 million to identifiable intangible assets. We expect that all of the acquired goodwill will be deductible for tax purposes. The purchase price allocations for the businesses acquired in March and November of 2017 are still preliminary and subject to change during their respective measurement periods. The purchase price allocation for the business acquired in January 2017 has been finalized during the fourth quarter of 2017 with an insignificant impact. The acquisition of these businesses was accounted for by the acquisition method, and the prices paid for them have been allocated to their respective assets and liabilities, based upon the estimated fair value of their assets and liabilities at the dates of their respective acquisitions by us. On April 15, 2016, we completed the acquisition of Ardent Services, L.L.C. and Rabalais Constructors, LLC (collectively, “Ardent”). This acquisition has been included in our United States electrical construction and facilities services segment. Ardent provides electrical and instrumentation services to the energy infrastructure market in North America, and this acquisition further strengthens our position in electrical construction and services and broadens our capabilities across the industrial and energy sectors, especially in the Gulf Coast, Midwest and Western regions of the United States. Under the terms of the transaction, we acquired 100% of Ardent’s equity interests for total consideration of $201.4 million. In connection with the acquisition of Ardent, we acquired working capital of $34.1 million and other net assets of $3.9 million and have ascribed $121.9 million to goodwill and $41.5 million to identifiable intangible assets. We expect that $99.7 million of the acquired goodwill will be deductible for tax purposes. The weighted average amortization period for the identifiable intangible assets is approximately 13.5 years. We completed the final allocation of Ardent’s purchase price during the first quarter of 2017 with an insignificant impact. On April 1, 2016, we acquired a company for an immaterial amount. This company provides mobile mechanical services within the Southeastern region of the United States, and its results have been included in our United States building services segment. The purchase price for this acquisition was finalized in 2016. On each of October 19, 2015, October 13, 2015 and June 1, 2015, we acquired a company, each for an immaterial amount. Two of the companies acquired primarily provide mechanical construction services, and their results of operations have been included in our United States mechanical construction and facilities services segment. The results of operations for the other company acquired have been included in our United States building services segment. The purchase prices paid for these acquisitions were finalized in 2016 with an insignificant impact.

ACQUISITIONS OF BUSINESSES

On January 4, 2017, March 1, 2017 and November 1, 2017, we acquired three companies for a total consideration of $109.3 million. One company provides fire protection and alarm services primarily in the Southern region of the United States. The second company provides millwright services for manufacturing companies throughout the United States. Both of their results have been included in our United States mechanical construction and facilities services segment. The third company provides mobile mechanical services within the Western region of the United States, and its results have been included in our United States building services segment. In connection with these acquisitions, we acquired working capital of $9.8 million and other net assets of $2.3 million and have preliminarily ascribed $40.6 million to goodwill and $56.6 million to identifiable intangible assets. We expect that all of the acquired goodwill will be deductible for tax purposes.

The purchase price allocations for the businesses acquired in March and November of 2017 are still preliminary and subject to change during their respective measurement periods. The purchase price allocation for the business acquired in January 2017 has been finalized during the fourth quarter of 2017 with an insignificant impact. The acquisition of these businesses was accounted for by the acquisition method, and the prices paid for them have been allocated to their respective assets and liabilities, based upon the estimated fair value of their assets and liabilities at the dates of their respective acquisitions by us.

On April 15, 2016, we completed the acquisition of Ardent Services, L.L.C. and Rabalais Constructors, LLC (collectively, “Ardent”). This acquisition has been included in our United States electrical construction and facilities services segment. Ardent provides electrical and instrumentation services to the energy infrastructure market in North America, and this acquisition further strengthens our position in electrical construction and services and broadens our capabilities across the industrial and energy sectors, especially in the Gulf Coast, Midwest and Western regions of the United States. Under the terms of the transaction, we acquired 100% of Ardent’s equity interests for total consideration of $201.4 million. In connection with the acquisition of Ardent, we acquired working capital of $34.1 million and other net assets of $3.9 million and have ascribed $121.9 million to goodwill and $41.5 million to identifiable intangible assets. We expect that $99.7 million of the acquired goodwill will be deductible for tax purposes. The weighted average amortization period for the identifiable intangible assets is approximately 13.5 years. We completed the final allocation of Ardent’s purchase price during the first quarter of 2017 with an insignificant impact.

On April 1, 2016, we acquired a company for an immaterial amount. This company provides mobile mechanical services within the Southeastern region of the United States, and its results have been included in our United States building services segment. The purchase price for this acquisition was finalized in 2016.

On each of October 19, 2015, October 13, 2015 and June 1, 2015, we acquired a company, each for an immaterial amount. Two of the companies acquired primarily provide mechanical construction services, and their results of operations have been included in our United States mechanical construction and facilities services segment. The results of operations for the other company acquired have been included in our United States building services segment. The purchase prices paid for these acquisitions were finalized in 2016 with an insignificant impact.