Long-Term Debt - Schedule of Long-Term Debt (Detail) - USD ($) $ in Millions |
Sep. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Feb. 28, 2014 |
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| Debt Instrument [Line Items] | ||||
| Other | $ 3.7 | $ 7.9 | ||
| Total | 2,446.6 | 2,268.1 | ||
| Less: current portion | 672.2 | 102.4 | ||
| Long-term portion | 1,774.4 | 2,165.7 | ||
| 2.00% Convertible Senior Notes Due 2019 [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Convertible senior notes, carrying value of liability component | 649.1 | 1,070.0 | ||
| Total | $ 930.9 | |||
| 2.625% Convertible Senior Notes Due 2024 [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Convertible senior notes, carrying value of liability component | 410.9 | |||
| Total | $ 410.1 | |||
| 7.250% Senior Notes Due 2026 [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Senior notes, carrying value | 394.6 | |||
| 2017 Senior Secured Credit Facility [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Borrowings under senior secured credit facility, carrying value | $ 1,190.2 | |||
| 2018 Senior Secured Credit Facility [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Borrowings under senior secured credit facility, carrying value | $ 988.3 |
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- Definition Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of long-term debt classified as other. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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