Oil and natural gas properties (Tables)

12 Months Ended

Dec. 31, 2014

Extractive Industries [Abstract]

Results of Operations for Oil and Gas Producing Activities Disclosure

Oil and natural gas properties are comprised of the following:

	December 31,
	2014			2013
Proved property	$	8,903,060		$	7,694,412
Unproved property	1,365,951			321,124
Work in process	—			25,897
Total oil and natural gas properties, at cost	10,269,011			8,041,433
Less: accumulated impairment	(7,430,438		)	(4,325,785		)
Oil and natural gas properties, net of impairment	2,838,573			3,715,648
Less: accumulated depletion	(1,942,380		)	(1,517,836		)
Oil and natural gas properties, net	896,193			2,197,812