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Debt - Narrative (Details) shares in Millions | 1 Months Ended | 3 Months Ended |  |
--- | --- | --- | --- | ---
Apr. 30, 2017 USD ($) shares | Mar. 31, 2017 USD ($) | Mar. 21, 2017 USD ($) | Dec. 31, 2016 USD ($)
Debt Instrument [Line Items] |  |  |  |
Long-term debt, par value |  | $ 1,189,500,000 |  | $ 1,189,500,000
Revolving credit facility |  | $ 150,000,000 |  | 0
Convertible Senior Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Stated interest rate (in hundredths) |  | 5.00% |  |
Long-term debt, par value |  | $ 145,000,000 |  | 145,000,000
Convertible Senior Notes | 2% Convertible Senior Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Stated interest rate (in hundredths) |  | 2.00% |  |
Convertible Senior Notes | 2% Convertible Senior Notes | Subsequent Event |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Shares issued during period upon conversion of convertible debt (in shares) | shares | 29.1 |  |  |
2% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Stated interest rate (in hundredths) |  | 2.00% |  |
Long-term debt, par value |  | $ 207,600,000 |  | 207,600,000
Conversion rate (in shares per $1,000 note) |  | 0.1438332 |  |
2% Notes | Subsequent Event |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Principal amount of notes converted into shares | $ 202,500,000 |  |  |
Principal amount of notes redeemed for cash | $ 5,100,000 |  |  |
Line of Credit | Revolving Credit Facility |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Maximum borrowing capacity |  |  | $ 175,000,000 |
Revolving credit facility |  | $ 150,000,000 |  |
9% Debentures |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Stated interest rate (in hundredths) |  | 9.00% |  |
Long-term debt, par value |  | $ 256,900,000 |  | $ 256,900,000
Conversion rate (in shares per $1,000 note) |  | 0.0740741 |  |

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- Definition Long-term Debt, Outstanding Principal Of Notes Redeemed For Cash + References No definition available. + Details
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- Definition Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 + Details
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- Definition Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Conversion Rate -URI http://asc.fasb.org/extlink&oid=6509012 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(5)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 + Details
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
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