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Related Parties (Details) - USD ($) $ in Millions	Jan. 01, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Wispark LLC
Related parties
Notes receivable, from buyer					$ 7.0
Bostco \| Wispark LLC
Related parties
Accounts receivable, related parties, current					$ 7.0
ATC
Related parties
Equity method investment, ownership percentage				23.00%
Equity method investment transfer to affiliated company	$ 402.0
Dividend receivable related to equity method investment transfer to affiliated company	13.4
Transfer of deferred income tax related to ATC to affiliated company	$ 186.8
Accounts receivable, related parties, current		$ 1.7	$ 2.2
Accounts payable, related parties, current		$ 19.9	$ 19.4