(Legal Proceedings) (Details) - complaint				1 Months Ended
	Aug. 10, 2017	Apr. 26, 2017	Aug. 17, 2016	Dec. 29, 2016
Securities Complaints
Loss Contingencies [Line Items]
Number of complaints			3
Derivative Complaints
Loss Contingencies [Line Items]
Number of complaints				2
Barnes Complaint
Loss Contingencies [Line Items]
Number of complaints		2
Barnes Complaint | Subsequent Event
Loss Contingencies [Line Items]
Litigation response period	60 days