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Goodwill and Other Intangibles - Changes in Goodwill (Detail) $ in Thousands | 9 Months Ended
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Sep. 30, 2018 USD ($)
Goodwill [Line Items] |
Balance at January 1, 2018 | $ 2,160,290
Acquisitions | 240,071
Divestitures | (927)
Balance at September 30, 2018 | 2,399,434
Mid-America Group |
Goodwill [Line Items] |
Balance at January 1, 2018 | 281,403
Acquisitions | 147,333
Balance at September 30, 2018 | 428,736
Southeast Group |
Goodwill [Line Items] |
Balance at January 1, 2018 | 50,346
Acquisitions | 92,738
Divestitures | (927)
Balance at September 30, 2018 | 142,157
West Group |
Goodwill [Line Items] |
Balance at January 1, 2018 | 1,828,541
Balance at September 30, 2018 | $ 1,828,541

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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + 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 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
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- Definition Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + 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 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
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