Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Amount accrued			$ 0.2	$ 2.2
Amount accrued current portion			0.2	$ 2.2
2017			$ 97.2
Transportation capacity agreements	$ 1.6	$ 52.9