Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Tables)

9 Months Ended

Sep. 30, 2012

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

	September 30, 2012		December 31, 2011
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	7,219,474	$	6,035,429
Unproved properties		781,371		748,598
Total		8,000,845		6,784,027
Accumulated depreciation, depletion and amortization		(1,942,698)		(1,626,461)
Net capitalized costs	$	6,058,147	$	5,157,566

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