Net Income Per Share (TEU) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
Sep. 17, 2018	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Tangible equity units proceeds	$ 800.2
Price for basic share (usd per share)	$ 0.3134
Price for shares diluted (usd per share)	$ 0.3839
Difference amount between basic and diluted net income per share		$ 0.01	$ 0.01
Net income allocated to PRS		$ 0.1	$ 0.3

Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=96947427&loc=SL5780133-109256

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration