Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Summary of Significant Accounting Policies

Schedule of Property, Plant and Equipment

	As of December 31,
	2013			2012
	(Thousands)
Oil and gas producing properties, successful efforts method	$	8,152,951		$	6,750,343
Accumulated depletion	(2,134,953		)	(1,572,775		)
Net oil and gas producing properties	6,017,998			5,177,568
Midstream plant	2,807,165			2,308,362
Accumulated depreciation and amortization	(547,991		)	(483,358		)
Net midstream plant	2,259,174			1,825,004
Other properties, at cost less accumulated depreciation	56,590			56,840
Net property, plant and equipment	$	8,333,762		$	7,059,412

Schedule of regulated net revenues and operating expenses

	Years Ended December 31,
	2013		2012		2011
	(Thousands)
Midstream revenues	$	184,767	$	131,184	$	113,774
Midstream operating expenses	$	71,517	$	66,202	$	76,247

Regulated net property, plant and equipment

	As of December 31,
	2013			2012
	(Thousands)
Property, plant & equipment	$	1,015,118		$	797,405
Accumulated depreciation and amortization	(158,533		)	(143,714		)
Net property, plant & equipment	$	856,585		$	653,691

Schedule of other current liabilities

	December 31,
	2013		2012
	(Thousands)
Incentive compensation	$	65,053	$	52,291
Taxes other than income	39,073		37,048
Accrued interest payable	29,379		29,878
All other accrued liabilities	18,763		27,388
Total other current liabilities	$	152,268	$	146,605

Reconciliation of the beginning and ending carrying amounts of asset retirement obligations

	Years Ended December 31,
	2013			2012
	(Thousands)
Asset retirement obligation as of beginning of period	$	109,034		$	102,439
Accretion expense	8,342			7,716
Liabilities incurred	2,510			1,141
Liabilities settled	(3,353		)	(2,408)
Revisions in estimated cash flows	(488		)	146
Asset retirement obligation as of end of period	$	116,045		$	109,034

Schedule of components of accumulated OCI, net of tax

	As of December 31,
	2013		2012
	(Thousands)
Net unrealized gain from natural gas hedging transactions	$	61,699	$	138,188
Net unrealized loss from interest rate swaps	(1,132)		(1,276)
Pension and other post-retirement benefits liability adjustment	(15,864)		(37,365)
Accumulated OCI	$	44,703	$	99,547