Commitments and contingencies Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2013

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:

2014	$	2,506
2015	2,552
2016	1,289
2017	1,289
2018	2,008
2019 and thereafter	10,186
	$	19,830