Capitalized Costs and Accumulated Depreciation Depletion and Amortization

6 Months Ended

Jun. 30, 2011

Extractive Industries [Abstract]

CAPITALIZED COSTS AND ACCUMULATED DEPRECIATION, DEPLETION AND AMORTIZATION

(17) CAPITALIZED COSTS AND ACCUMULATED DEPRECIATION, DEPLETION AND AMORTIZATION^(a)

	June 30,			December 31,
	2011			2010
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	5,326,056		$	4,742,248
Unproved properties		673,609			648,143
Total		5,999,665			5,390,391
Accumulated depreciation, depletion and amortization		(1,447,300	)		(1,306,378	)
Net capitalized costs	$	4,552,365		$	4,084,013

^(a) Includes capitalized asset retirement costs and associated accumulated amortization.