Costs Incurred for Property Acquisition, Exploration and Development (Tables)

9 Months Ended

Sep. 30, 2017

Extractive Industries [Abstract]

Costs Incurred for Property Acquisition, Exploration and Development

	Nine Months Ended September 30, 2017		Year Ended December 31, 2016
	(in thousands)
Acquisitions:
Acreage purchases	$	41,817	$	33,142
Oil and gas properties		7,875		3,098,772
Asset retirement obligations		—		21,908
Development		809,961		497,795
Exploration:
Drilling		1,008		37,680
Expense		44,173		30,027
Stock-based compensation expense		1,596		2,298
Gas gathering facilities:
Development		6,292		3,595
Subtotal		912,722		3,725,217
Asset retirement obligations		6,460		(24,064	)
Total costs incurred	$	919,182	$	3,701,153

^(a) Includes costs incurred whether capitalized or expensed.