Organization and Basis of Presentation - ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017
Organization and Basis of Presentation
Corporate tax rate (as a percent)		21.00%	35.00%
Reclassification of tax effects stranded in accumulated other comprehensive income	$ 20.1

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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