Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Oil and gas revenues	$ 144,329	$ 96,197	$ 390,454	$ 260,730
Cost and expenses	95,726	71,879	261,770	199,226
OPERATING INCOME	48,603	24,318	128,684	61,504
Other income (expense), net	(41,032)	(26,855)	(58,758)	(6,118)
Income (loss) from continuing operations before income taxes	7,571	(2,537)	69,926	55,386
Income tax (expense) benefit	(1,859)	592	(25,853)	(20,972)
Equity in income (loss) of subsidiaries	0	0	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	5,712	(1,945)	44,073	34,414
Net income from discontinued operations, net of income taxes	(1,191)	1,015	23,599	2,583
NET INCOME (LOSS)	4,521	(930)	67,672	36,997
Parent Company [Member]
Oil and gas revenues	2,428	4,459	6,075	15,856
Cost and expenses	20,994	15,256	57,427	62,608
OPERATING INCOME	(18,566)	(10,797)	(51,352)	(46,752)
Other income (expense), net	(36,314)	(16,407)	(41,995)	18,890
Income (loss) from continuing operations before income taxes	(54,880)	(27,204)	(93,347)	(27,862)
Income tax (expense) benefit	19,208	9,531	32,671	9,760
Equity in income (loss) of subsidiaries	40,759	17,374	106,218	47,847
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	5,087	(299)	45,542	29,745
Net income from discontinued operations, net of income taxes	(1,191)	0	23,599	0
NET INCOME (LOSS)	3,896	(299)	69,141	29,745
Combined Guarantor Subsidiaries [Member]
Oil and gas revenues	141,901	91,738	384,379	244,874
Cost and expenses	74,640	56,135	204,204	150,242
OPERATING INCOME	67,261	35,603	180,175	94,632
Other income (expense), net	(4,718)	(10,448)	(16,763)	(25,008)
Income (loss) from continuing operations before income taxes	62,543	25,155	163,412	69,624
Income tax (expense) benefit	(21,784)	(8,796)	(57,194)	(24,360)
Equity in income (loss) of subsidiaries	0	0	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	40,759	16,359	106,218	45,264
Net income from discontinued operations, net of income taxes	0	0	0	0
NET INCOME (LOSS)	40,759	16,359	106,218	45,264
Combined Non-Guarantor Subsidiaries [Member]
Oil and gas revenues	0	0	0	0
Cost and expenses	0	0	0	0
OPERATING INCOME	0	0	0	0
Other income (expense), net	0	0	0	0
Income (loss) from continuing operations before income taxes	0	0	0	0
Income tax (expense) benefit	0	0	0	0
Equity in income (loss) of subsidiaries	0	0	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	0	0	0	0
Net income from discontinued operations, net of income taxes	0	1,015	0	2,583
NET INCOME (LOSS)	0	1,015	0	2,583
Eliminations [Member]
Oil and gas revenues	0	0	0	0
Cost and expenses	92	488	139	(13,624)
OPERATING INCOME	(92)	(488)	(139)	13,624
Other income (expense), net	0	0	0	0
Income (loss) from continuing operations before income taxes	(92)	(488)	(139)	13,624
Income tax (expense) benefit	717	(143)	(1,330)	(6,372)
Equity in income (loss) of subsidiaries	(40,759)	(17,374)	(106,218)	(47,847)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(40,134)	(18,005)	(107,687)	(40,595)
Net income from discontinued operations, net of income taxes	0	0	0	0
NET INCOME (LOSS)	$ (40,134)	$ (18,005)	$ (107,687)	$ (40,595)