Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2017

Derivative [Line Items]

Fair Value of Financial Assets and Liabilities

The tables below summarize the balances of commodity derivative assets and liabilities at March 31, 2017 and December 31, 2016 (in thousands):

	March 31, 2017							December 31, 2016
Derivatives subject to netting arrangements:	Level 1		Netting*			Total		Level 1		Netting*			Total
Commodity derivatives:
Assets	$	63	$	(63	)	$	—	$	68	$	(68	)	$	—
Liabilities	$	1,418	$	(63	)	$	1,355	$	1,396	$	(68	)	$	1,328

*Relates primarily to exchange traded futures. Gain and loss positions on multiple contracts are settled net on a daily basis with the exchange.

Schedule of Notional Quantities for Commodity Derivative Instruments

The following table sets forth the notional quantities for commodity derivative instruments entered into (in thousands of barrels):

	Three Months Ended March 31,
	2017	2016
Sales	4,312	10,420
Purchases	4,131	10,510

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]

We have recorded the fair value of our commodity derivative instruments on our condensed consolidated balance sheets in "other current assets" and "other current liabilities" in the following amounts (in thousands):

	March 31, 2017				December 31, 2016
	Assets		Liabilities		Assets		Liabilities
Commodity contracts	$	—	$	1,355	$	—	$	1,328

Schedule of Realized and Unrealized Gains (Losses) from Commodity Derivatives

Realized and unrealized gains (losses) from our commodity derivatives were recorded to product revenue in the following amounts (in thousands):

	Three Months Ended March 31,
	2017		2016
Commodity contracts	$	4,661	$	3,354