Oil and Gas Producing Activities

12 Months Ended

Dec. 31, 2017

Oil And Gas Exploration And Production Industries Disclosures [Abstract]

Oil and Gas Producing Activities

(3)  Oil and Gas Producing Activities

Set forth below is certain information regarding the aggregate capitalized costs of oil and gas properties and costs incurred by the Company for its oil and gas property acquisition, development and exploration activities:

Capitalized Costs

	As of December 31,
	2016			2017
	(In thousands)
Proved properties:
Leasehold costs	$	662,022		$	491,507
Wells and related equipment and facilities		3,135,079			2,140,243
Accumulated depreciation depletion and amortization		(3,009,236	)		(2,032,927	)
	$	787,865		$	598,823

Costs Incurred

	For the Years Ended December 31,
	2015		2016		2017
	(In thousands)
Unproved property acquisitions	$	12,972	$	—	$	—
Development costs		221,265		58,587		177,432
Exploration costs		12,265		—		—
	$	246,502	$	58,587	$	177,432