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Basis of Presentation - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |  |  |
Total costs and expenses | $ 189.6 | $ 179.5 | $ 292.3 | $ 351.3
Operating income (loss) | 4.4 | 17.0 | 91.9 | 22.6
Total other income (expense) | $ (0.7) | (4.9) | $ (1.6) | (6.5)
Overstated [Member] |  |  |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |  |  |
Total costs and expenses |  | 3.8 |  | 3.2
Understated [Member] |  |  |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |  |  |
Operating income (loss) |  | 3.8 |  | 3.2
Total other income (expense) |  | $ 3.8 |  | $ 3.2
Assurex [Member] |  |  |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |  |  |
Non controlling interest ownership percentage by parent | 85.00% |  | 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% |  | 15.00% |

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