| Employee Defined Benefit Retirement Plans (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| Jun. 30, 2021 | Jun. 30, 2021 | Dec. 31, 2020 | Jul. 31, 2020 | |
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Retirement plan liability | $ 7.9 | |||
| Net periodic benefit cost | $ 0.1 | $ 0.2 | ||
| Other Long-term Investments | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Defined benefit obligation | $ 6.3 | $ 6.3 | $ 6.4 | 
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- Definition Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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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 Amount of liability, recognized in statement of financial position, for pension, other postretirement and postemployment benefits. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Details 
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