Commitments and Contingencies Legal Proceedings (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Liability insurance coverage, retention amount		$ 2.0
Refinery outage [Member]
Loss Contingencies [Line Items]
Damages sought	$ 48.5	$ 108.0	$ 61.7