Segment Information (Tables)

12 Months Ended

Dec. 31, 2011

Segment Information [Abstract]

Summary Financial Information for Company's Reportable Segments Table

	Exploration
	And		Midstream
	Production		Services	Other	Total
	(in thousands)
2011
Revenues from external customers	$   2,088,763		$       864,096	$                 47	$    2,952,906
Intersegment revenues	11,725		1,995,423	3,221	2,010,369
Operating income	825,138		247,952	1,711	1,074,801
Other income, net(1)	328		(91)	27	264
Depreciation, depletion and amortization expense	666,125		37,261	1,125	704,511
Interest expense(1)	9,026		15,049	0	24,075
Provision for income taxes(1)	322,714		90,221	286	413,221
Assets	6,547,117	(2)	1,119,861	235,919	7,902,897
Capital investments(3)	1,977,493		160,776	68,905	2,207,174
2010
Revenues from external customers	$   1,871,835		$       738,828	$                 0	$    2,610,663
Intersegment revenues	18,609		1,715,012	984	1,734,605
Operating income	829,462		191,566	200	1,021,228
Other income, net(1)	235		179	13	427
Depreciation, depletion and amortization expense	561,018		28,765	549	590,332
Interest expense(1)	7,888		18,275	0	26,163
Provision for income taxes(1)	323,748		67,834	77	391,659
Assets	4,849,478	(2)	1,016,563	151,422	6,017,463
Capital investments(3)	1,775,518		271,316	73,231	2,120,065
2009
Revenues from external customers	$   1,582,596		$       562,944	$               239	$    2,145,779
Intersegment revenues	10,635		1,040,388	448	1,051,471
Operating income (loss)	(157,725)		122,620	139	(34,966)
Other income, net(1)	1,406		34	9	1,449
Depreciation, depletion and amortization expense	474,014		19,213	431	493,658
Impairment of natural gas and oil properties	907,812		0	0	907,812
Interest expense(1)	15,237		3,401	0	18,638
Provision (benefit) for income taxes(1)	(61,725)		45,303	59	(16,363)
Assets	3,904,739	(2)	767,346	98,165	4,770,250
Capital investments(3)	1,565,450		214,208	29,459	1,809,117