v3.20.2
FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($)
$ in Millions
Sep. 27, 2020
Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents, fair value $ 31.0 $ 132.6
Fair Value, Inputs, Level 2 | Senior Notes | 7.50% Senior Notes Due 2027    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of senior notes 326.1 320.3
Fair Value, Inputs, Level 2 | 1.0% Convertible Notes Due 2023 | Convertible Senior Notes Due 2023    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of convertible debt $ 166.9 $ 162.5