Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Long-term Purchase Commitment [Line Items]

Supply Commitment [Table Text Block]

At December 31, 2016, such commitments included the following (in thousands):

	Volume (barrels)	Value
Fixed price purchases	2,359	$	120,064
Fixed price sales	8,670	$	453,647
Floating price purchases	3,577	$	179,237
Floating price sales	13,573	$	738,245

Summary of Changes in Asset Retirement Obligations

The following table summarizes the changes in this liability from December 31, 2013 through December 31, 2016 (in thousands):

Balance, December 31, 2013	$	41,185
Accretion	4,807
Payments made	(514		)
Currency translation adjustments	(3,524		)
Balance, December 31, 2014	41,954
Accretion	4,748
Payments made	(511		)
Revaluation	(26,000		)
Currency translation adjustments	(4,245		)
Balance, December 31, 2015	15,946
Accretion	2,292
Payments made	(159		)
Currency translation adjustments	469
Balance, December 31, 2016	$	18,548

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Future minimum payments required under operating leases that have initial or remaining non-cancellable lease terms in excess of one year at December 31, 2016, are as follows (in thousands):

For year ending:
December 31, 2017	$	4,516
December 31, 2018	4,218
December 31, 2019	3,871
December 31, 2020	3,517
December 31, 2021	3,545
Thereafter	10,018
Total future minimum lease payments	$	29,685

Summary of Purchase and Sale Commitments [Table Text Block]

At December 31, 2016, such commitments included the following (in thousands):

	Volume (barrels)	Value
Fixed price purchases	2,359	$	120,064
Fixed price sales	8,670	$	453,647
Floating price purchases	3,577	$	179,237
Floating price sales	13,573	$	738,245

Long-term Purchase Commitment [Table Text Block]

The approximate amount of future obligation is as follows (in thousands):

For year ending:
December 31, 2017	$	11,938
December 31, 2018	10,060
December 31, 2019	9,121
December 31, 2020	8,451
December 31, 2021	6,841
Thereafter	9,099
Total expected future payments	$	55,510