Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Current assets:
Cash and cash equivalents	$ 13,757	$ 2,976	$ 6,095
Accounts receivable:
Trade, net of allowance for bad debt of $520 and $535, respectively	82,558	63,690
Accrued revenue and other	121,527	155,828
Derivative Asset, Current	1,110	3,234
Natural gas and natural gas liquids inventory, prepaid expenses and other	20,736	11,866
Assets held for disposition	0	22,599
Total current assets	239,688	260,193
Property and equipment, net of accumulated depreciation of $574,414 and $504,442, respectively	1,849,902	1,472,161
Intangible assets, net of accumulated amortization of $219,056 and $263,305, respectively	325,154	425,005
Goodwill	153,802	152,627
Investment in limited liability company	99,561	90,500
Other assets, net	24,458	25,989
Total assets	2,692,565	2,426,475	2,353,874
Current liabilities:
Accounts payable, drafts payable and other	35,962	32,265
Accrued gas and crude oil purchases	127,533	140,344
Derivative Liability, Current	600	1,310
Other current liabilities	82,750	71,916
Accrued Interest	16,062	26,712
Liabilities held for disposition	0	3,572
Total current liabilities	262,907	276,119
Long-term debt	1,102,357	1,036,305
Other long-term liabilities	27,888	30,256
Deferred tax liability	123,543	133,555
Derivative Instruments and Hedges, Liabilities, Noncurrent	19		0
Commitments and contingencies
Stockholders' Equity	1,175,851	950,240
Total liabilities and Stockholders' equity	$ 2,692,565	$ 2,426,475