Property And Equipment, Net (Narrative) (Details) (USD $)	1 Months Ended		3 Months Ended				6 Months Ended	12 Months Ended						1 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Utica [Member] Avista Joint Venture [Member]	Jan. 15, 2013 Utica [Member] Avista Joint Venture [Member]	Oct. 31, 2012 Utica [Member] Avista Joint Venture [Member]	Oct. 31, 2012 Niobrara Formation - OIL India Ltd And Indian Oil Corporation Ltd [Member]	Oct. 31, 2012 Niobrara Formation - Haimo Oil And Gas LLC [Member]	Oct. 31, 2012 Carrizo [Member]
Property, Plant and Equipment [Line Items]
Costs not subject to amortization			$ 377,437,000				$ 377,437,000	$ 377,437,000	$ 323,688,000
Capitalized costs of unproved properties								265,000,000	112,400,000
Proceeds from sale of property		51,700,000			17,600,000	187,100,000	29,500,000	238,470,000	341,597,000	167,265,000	51,700,000			41,250,000	27,500,000
Sale price of oil and gas property and equipment				218,000,000	19,300,000	190,000,000	30,500,000
Net proceeds from sale of properties			191,800,000
Percent of total proved reserves that were sold				40.00%
Loss on sale of oil and gas properties								(45,377,000)	0	0
Joint venture investment, original ownership percentage												10.00%	10.00%
Joint venture investment, net proceeds ownership percentage													50.00%
Payments to Acquire Oil and Gas Property	78,600,000		63,100,000
Joint venture investment, ownership percentage														30.00%	10.00%	60.00%
Future development costs payment percentage														50.00%
Maximum future development costs receivable														$ 41,250,000