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Basis of Presentation - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Sep. 30, 2017 | Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Total costs and expenses | $ 102.8 | $ 171.8
Operating income (loss) | 87.4 | 5.7
Other income (expense) | (0.3) | (1.3)
Total other income | (0.8) | $ (1.7)
Understated [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Total costs and expenses | 0.5 |
Operating income (loss) | 0.5 |
Overstated [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Other income (expense) | 0.5 |
Total other income | $ 0.5 |
Assurex [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Non controlling interest ownership percentage by parent | 85.00% |
Centre For Addiction And Mental Health [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Non controlling interest ownership percentage by noncontrolling owners | 15.00% |

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