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

6 Months Ended

Jun. 30, 2013

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

	June 30, 2013			December31, 2012
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	7,645,140		$	7,368,308
Unproved properties		724,501			743,467
Total		8,369,641			8,111,775
Accumulated depreciation, depletion and amortization		(2,035,850	)		(2,015,591	)
Net capitalized costs	$	6,333,791		$	6,096,184

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