Debt (Schedule of Debt) (Details) - USD ($) |
Oct. 31, 2020 |
Aug. 01, 2020 |
Jul. 23, 2020 |
Aug. 21, 2015 |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Debt Instrument [Line Items] | ||||||||||||||||
| Long-term debt | $ 1,382,600,000 | $ 1,480,500,000 | ||||||||||||||
| Long-term Debt, Current Maturities | 0 | (227,900,000) | ||||||||||||||
| Total long-term debt | 292,400,000 | 0 | ||||||||||||||
| Liabilities Subject to Compromise | ||||||||||||||||
| Debt Instrument [Line Items] | ||||||||||||||||
| Long-term Debt, Current Maturities | [1],[2] | (1,090,200,000) | (1,252,600,000) | |||||||||||||
| Term Loan | ||||||||||||||||
| Debt Instrument [Line Items] | ||||||||||||||||
| Long-term debt, including unamortized original issue discount and debt issuance costs | 1,421,600,000 | [3] | 1,271,600,000 | [3] | $ 1,800,000,000 | |||||||||||
| Less: unamortized debt issuance costs | [3],[4] | (24,100,000) | (10,100,000) | |||||||||||||
| Less: unamortized original issue discount | [3],[4] | (8,900,000) | (8,900,000) | |||||||||||||
| Long-term debt | [3] | $ 1,388,600,000 | 1,252,600,000 | |||||||||||||
| Debt effective interest rate (percent) | 6.30% | |||||||||||||||
| Secured Debt | Backstop Parties | Debtor-in-Possession Term Loan Credit Facility (DIP Term Facility) | ||||||||||||||||
| Debt Instrument [Line Items] | ||||||||||||||||
| Less: unamortized debt issuance costs | $ 14,000,000.0 | |||||||||||||||
| Debt | $ 312,300,000 | |||||||||||||||
| Revolving Credit Facility [Member] | ||||||||||||||||
| Debt Instrument [Line Items] | ||||||||||||||||
| Long-term debt, including unamortized original issue discount and debt issuance costs | 0 | 230,000,000.0 | ||||||||||||||
| Less: unamortized debt issuance costs | [5] | (6,000,000.0) | (2,100,000) | |||||||||||||
| Long-term debt | $ (6,000,000.0) | $ 227,900,000 | ||||||||||||||
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