Leases (Summary of Commitments Relating to Non-Cancellable Operating and Capital Leases) (Parenthetical) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Leases [Abstract]
Operating leases, future minimum sublease rentals due	$ 3.8

Contractually required future rental payments receivable on noncancelable subleasing arrangements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant