Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Variable Interest Entity, Primary Beneficiary \| KFPC
Related Party Transaction [Line Items]
Outstanding payables	$ 1.3		$ 0.8
Variable interest entity, ownership percentage	50.00%
Purchases from related party	$ 11.8	$ 5.9
Styrenic Block Copolymer Joint Venture
Related Party Transaction [Line Items]
Percentage of equity investment	50.00%
Outstanding payables	$ 15.9		$ 20.1
Related party liability	$ 8.2	$ 9.1

Carrying amount as of the balance sheet date of obligations due all related parties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

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