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

3 Months Ended

Mar. 31, 2014

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

	March 31, 2014			December 31, 2013
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	8,467,064		$	8,225,859
Unproved properties		842,679			807,022
Total		9,309,743			9,032,881
Accumulated depreciation, depletion and amortization		(2,397,089	)		(2,274,444	)
Net capitalized costs	$	6,912,654		$	6,758,437

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