Supplemental disclosures to the consolidated statements of cash flows (Tables)

12 Months Ended

Dec. 31, 2014

Supplemental Cash Flow Elements [Abstract]

Supplemental disclosures to the consolidated statements of cash flows

Supplemental disclosures to the consolidated statements of cash flows are presented below:

	Year ended December 31,
	2014			2013			2012
Net cash provided by operating activities included:
Cash payments for interest	$	112,196		$	107,122		$	103,350
Interest capitalized	(13,491		)	(15,995		)	(4,437		)
Cash payments for interest, net of amounts capitalized	$	98,705		$	91,127		$	98,913
Cash payments for income taxes	$	591		641			255
Non-cash investing activities included:
Asset retirement obligation additions and revisions	$	7,461		$	9,036		$	1,079
Oil and natural gas properties acquired through increase in accounts payable and accrued liabilities	$	43,971		$	27,875		$	24,280