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DELL APPRAISAL RIGHTS MATTER. (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 14, 2017	Dec. 30, 2016	Mar. 31, 2017	Sep. 30, 2018	Dec. 31, 2016
Dell appraisal rights matter [Member]
Unusual or Infrequent Item [Line Items]
Nonrecurring charge, net of insurance recovery, related to Dell appraisal rights matter					$ 166.2
Insurance proceeds		$ 100.0	$ 50.0
Price offered per share in Dell merger (in dollars per share)	$ 13.75
Dell appraisal rights matter [Member] | Minimum [Member]
Unusual or Infrequent Item [Line Items]
Price settled per share in Dell merger (in dollars per share)				$ 13.75
Dell appraisal rights matter [Member] | Maximum [Member]
Unusual or Infrequent Item [Line Items]
Price settled per share in Dell merger (in dollars per share)				$ 13.83
Dell appraisal rights matter [Member]
Unusual or Infrequent Item [Line Items]
Unrecorded gain contingency				$ 15.2

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- Definition

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- Definition

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+ References

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Amount, before deduction of insurance proceeds, of loss recognized in the income statement for an event or transaction that is unusual in nature or infrequent in occurrence, or both.

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