Commitments and Contingencies Crude Oil Releases (Details) $ in Millions	Sep. 30, 2016 USD ($)	Jan. 31, 2016 bbl	Apr. 30, 2015 bbl	Mar. 31, 2013 bbl
Modisette Release [Member]
Loss Contingencies [Line Items]
Crude oil released (barrels)		30
Paline Release [Member]
Loss Contingencies [Line Items]
Crude oil released (barrels)		350
Accrual for Environmental Loss Contingencies | $	$ 0.1
Fouke Release [Member]
Loss Contingencies [Line Items]
Crude oil released (barrels)			130
Magnolia Release [Member]
Loss Contingencies [Line Items]
Crude oil released (barrels)				5,900
Accrual for Environmental Loss Contingencies | $	$ 1.0