Revenues (Narrative) (Details) $ in Millions	1 Months Ended
Apr. 30, 2018 USD ($)
Subsequent Event [Member]
Lessor Lease Description [Line Items]
Payment accepted on termination of lease prior to contractual expiration	$ 4.3

Amount of gain (loss) on termination of lease before expiration of lease term.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 40
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77888415&loc=SL77918607-209975

Name:	us-gaap_GainLossOnTerminationOfLease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration