Condensed Consolidating Financial Statements (Schedule Of Condensed Consolidating Statement Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Net cash provided by (used in) operating activities	$ 268,122	$ 171,232
Additions to oil and natural gas properties, gathering assets and equipment and property acquisitions	(197,767)	(165,753)
Proceeds from disposition of property and equipment	76,266	613,090
Restricted cash	5,349	27,543
Net changes in advances to joint ventures	(10,540)	8,276
Equity method investments	1,749	(104)
Distributions received from Compass	0	0
Advances/investments with affiliates	0	0
Net cash provided by (used in) investing activities	(124,943)	483,052
Borrowings under credit agreements	0	46,757
Repayments under credit agreements	(882,424)	(644,541)
Proceeds received from 2022 Notes	500,000	0
Proceeds from issuance of common stock, net	271,772	42
Payment of common stock dividends	(27,066)	(21,479)
Compass cash distribution	0	0
Deferred financing costs and other	(10,066)	(265)
Net cash provided by (used in) financing activities	(147,784)	(619,486)
Net increase (decrease) in cash	(4,605)	34,798
Cash at beginning of period	50,483	45,644
Cash at end of period	45,878	80,442
Resources [Member]
Net cash provided by (used in) operating activities	(54,003)	(3,892)
Additions to oil and natural gas properties, gathering assets and equipment and property acquisitions	(1,639)	(8,907)
Proceeds from disposition of property and equipment	68,242	244,499
Restricted cash	0	0
Net changes in advances to joint ventures	0	0
Equity method investments	0	0
Distributions received from Compass	3,311	1,275
Advances/investments with affiliates	107,240	462,020
Net cash provided by (used in) investing activities	177,154	698,887
Borrowings under credit agreements		10,000
Repayments under credit agreements	(879,874)	(643,266)
Proceeds received from 2022 Notes	500,000
Proceeds from issuance of common stock, net	271,772	42
Payment of common stock dividends	(27,066)	(21,479)
Compass cash distribution	0	0
Deferred financing costs and other	(10,066)	(32)
Net cash provided by (used in) financing activities	(145,234)	(654,735)
Net increase (decrease) in cash	(22,083)	40,260
Cash at beginning of period	81,840	65,791
Cash at end of period	59,757	106,051
Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	310,651	168,302
Additions to oil and natural gas properties, gathering assets and equipment and property acquisitions	(193,606)	(120,434)
Proceeds from disposition of property and equipment	8,017	368,591
Restricted cash	5,349	27,543
Net changes in advances to joint ventures	(10,540)	8,276
Equity method investments	1,749	(104)
Distributions received from Compass	0	0
Advances/investments with affiliates	(107,240)	(462,020)
Net cash provided by (used in) investing activities	(296,271)	(178,148)
Borrowings under credit agreements		0
Repayments under credit agreements	0	0
Proceeds received from 2022 Notes	0
Proceeds from issuance of common stock, net	0	0
Payment of common stock dividends	0	0
Compass cash distribution	0	0
Deferred financing costs and other	0	0
Net cash provided by (used in) financing activities	0	0
Net increase (decrease) in cash	14,380	(9,846)
Cash at beginning of period	(35,892)	(20,147)
Cash at end of period	(21,512)	(29,993)
Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	11,474	6,822
Additions to oil and natural gas properties, gathering assets and equipment and property acquisitions	(2,522)	(36,412)
Proceeds from disposition of property and equipment	7	0
Restricted cash	0	0
Net changes in advances to joint ventures	0	0
Equity method investments	0	0
Distributions received from Compass	0	0
Advances/investments with affiliates	0	0
Net cash provided by (used in) investing activities	(2,515)	(36,412)
Borrowings under credit agreements		36,757
Repayments under credit agreements	(2,550)	(1,275)
Proceeds received from 2022 Notes	0
Proceeds from issuance of common stock, net	0	0
Payment of common stock dividends	0	0
Compass cash distribution	(3,311)	(1,275)
Deferred financing costs and other	0	(233)
Net cash provided by (used in) financing activities	(5,861)	33,974
Net increase (decrease) in cash	3,098	4,384
Cash at beginning of period	4,535	0
Cash at end of period	7,633	4,384
Eliminations [Member]
Net cash provided by (used in) operating activities	0	0
Additions to oil and natural gas properties, gathering assets and equipment and property acquisitions	0	0
Proceeds from disposition of property and equipment	0	0
Restricted cash	0	0
Net changes in advances to joint ventures	0	0
Equity method investments	0	0
Distributions received from Compass	(3,311)	(1,275)
Advances/investments with affiliates	0	0
Net cash provided by (used in) investing activities	(3,311)	(1,275)
Borrowings under credit agreements		0
Repayments under credit agreements	0	0
Proceeds received from 2022 Notes	0
Proceeds from issuance of common stock, net	0	0
Payment of common stock dividends	0	0
Compass cash distribution	3,311	1,275
Deferred financing costs and other	0	0
Net cash provided by (used in) financing activities	3,311	1,275
Net increase (decrease) in cash	0	0
Cash at beginning of period	0	0
Cash at end of period	$ 0	$ 0