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Business Acquisitions - Summary of Changes to Goodwill Balance (Detail) - USD ($) $ in Millions | 10 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2018 | Jun. 30, 2017
Goodwill [Line Items] |  |  |
Beginning balance |  | $ 316.1 | $ 195.3
Working capital adjustment |  | 1.9 | 3.6
Ending balance | $ 318.6 | 318.6 | $ 316.1
Assurex [Member] |  |  |
Goodwill [Line Items] |  |  |
Beginning balance | 119.2 |  |
Fair value adjustment to equipment and intangibles | (0.1) | (0.1) |
Working capital adjustment | 0.2 | 0.2 |
Change in deferred tax liability | 1.8 | 1.8 |
Ending balance | $ 121.1 | $ 121.1 |

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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 (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the 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 805 -SubTopic 10 -Section 25 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e961-128460 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
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