Derivatives - Narrative (Details) bbl in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) bbl	Sep. 30, 2016	Jun. 30, 2016 USD ($)
Interest Rate Swap
Credit Derivatives [Line Items]
Fixed interest rate		1.10%
Notional amount | $	$ 200,000,000
Forward Contracts | Over the Counter | Options Collar
Credit Derivatives [Line Items]
Derivative contracts, barrels	52
Forward Contracts | Over the Counter | Option Collars and Swap
Credit Derivatives [Line Items]
Derivative contracts, barrels	20
Long | Future | Over the Counter | Energy Related Derivative
Credit Derivatives [Line Items]
Derivative contracts, barrels	100
Long | Future | Over the Counter | Commodity Contract
Credit Derivatives [Line Items]
Derivative contracts, barrels	315
5% Convertible Senior Notes due 2021 | Convertible Debt
Credit Derivatives [Line Items]
Aggregate principal amount | $			$ 115,000,000