Debt (2016 Bridge Credit Agreement) (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Bridge Loan
Short-term Debt [Line Items]
Debt Related Commitment Fees and Debt Issuance Costs	$ 45.2

Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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