Commitments and contingencies Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Unrecorded Unconditional Purchase Obligations Disclosure

Based on current prices, our estimated minimum purchase obligations under our CO₂ contracts are as follows:

2015	$	2,556
2016	2,436
2017	1,289
2018	1,169
2019	1,196
2020 and thereafter	4,785
	$	13,431

Schedule of Future Minimum Rental Payments for Operating Leases

As of December 31, 2014, total remaining payments associated with our operating leases were:

2015	$	1,207
2016	1,200
2017	1,152
2018	1,104
2019	977
2020 and thereafter	1,977
	$	7,617