Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Long-term Purchase Commitment [Line Items]

Summary of Changes in Asset Retirement Obligations

The following table summarizes the changes in this liability from December 31, 2012 through December 31, 2015 (in thousands):

Balance, December 31, 2012	$	40,105
Accretion	4,752
Payments made	(808		)
Currency translation adjustments	(2,864		)
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

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, 2015 are as follows (in thousands):

For year ending:
December 31, 2016	$	9,218
December 31, 2017	7,001
December 31, 2018	3,055
December 31, 2019	1,941
December 31, 2020	157
Thereafter	6,814
Total future minimum lease payments	$	28,186

Summary of Purchase and Sale Commitments [Table Text Block]

At December 31, 2015, such commitments included the following (in thousands):

	Volume (barrels)	Value
Fixed price purchases	1,976	$	71,709
Fixed price sales	2,907	$	116,329
Floating price purchases	17,361	$	652,122
Floating price sales	19,691	$	709,991

Long-term Purchase Commitment [Table Text Block]

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

For year ending:
December 31, 2016	$	11,804
December 31, 2017	11,938
December 31, 2018	10,060
December 31, 2019	9,121
December 31, 2020	8,451
Thereafter	15,941
Total expected future payments	$	67,315