Transaction and Litigation Costs (Reimbursements) (Details) - Settlement of the Apple Ten Merger Litigation [Member] - USD ($) $ in Millions	1 Months Ended	12 Months Ended
May 31, 2017	Dec. 31, 2017
Transaction and Litigation Costs (Reimbursements) (Details) [Line Items]
Transaction and Litigation Costs (Reimbursements)	$ (2.6)	$ (2.6)
Proceeds from Insurance Settlement, Operating Activities	$ 2.6

Amount of cash inflow for proceeds from settlement of insurance claim, classified as operating activities. Excludes insurance settlement classified as investing activities.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3337-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21B
-URI http://asc.fasb.org/extlink&oid=118932676&loc=SL94080549-108585

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