PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Details) (USD $)	12 Months Ended					0 Months Ended	1 Months Ended	0 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended			1 Months Ended	12 Months Ended		1 Months Ended			1 Months Ended			3 Months Ended			0 Months Ended					0 Months Ended	1 Months Ended	12 Months Ended						0 Months Ended	1 Months Ended		0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Dec. 06, 2012 Stock Purchase Agreement CPPIB Private placement	Dec. 31, 2012 Stock Purchase Agreement CPPIB Private placement	Dec. 06, 2012 Williston Basin Assets	Dec. 31, 2013 Williston Basin Assets	Dec. 31, 2012 Williston Basin Assets	Jan. 18, 2013 Williston Basin Assets Petro-Hunt Parties	Aug. 02, 2012 GeoResources	Dec. 31, 2012 GeoResources	Aug. 02, 2012 East Texas Assets	Aug. 03, 2012 East Texas Assets	Aug. 03, 2012 East Texas Assets	Aug. 31, 2012 East Texas Assets	Dec. 31, 2012 East Texas Assets	Jul. 31, 2012 East Texas Assets	Feb. 29, 2012 February 2012 Warrants	Aug. 30, 2012 GeoResources Warrants GeoResources	Aug. 30, 2012 August 2012 Warrants GeoResources	Apr. 30, 2012 Convertible Preferred Stock Private placement	Mar. 31, 2012 Convertible Preferred Stock Private placement	Feb. 29, 2012 Convertible Preferred Stock Private placement	Jun. 30, 2012 Convertible Preferred Stock Private placement	Mar. 31, 2012 Convertible Preferred Stock Private placement	Mar. 05, 2012 Convertible Preferred Stock Private placement	Jan. 17, 2013 Convertible Preferred Stock Williston Basin Assets	Dec. 06, 2012 Convertible Preferred Stock Williston Basin Assets	Aug. 13, 2013 Common Stock	Feb. 08, 2012 Common Stock	Jan. 17, 2013 Common Stock	Apr. 17, 2012 Common Stock Private placement	Mar. 31, 2012 Common Stock Private placement	Dec. 31, 2013 Common Stock Private placement	Jan. 18, 2013 Common Stock Private placement	Mar. 28, 2012 Common Stock Private placement	Dec. 31, 2013 Common Stock Williston Basin Assets	Jan. 17, 2013 Common Stock Williston Basin Assets	Dec. 06, 2012 Common Stock Williston Basin Assets	Aug. 02, 2012 Common Stock GeoResources	Aug. 31, 2012 Common Stock GeoResources	Aug. 31, 2012 Common Stock East Texas Assets	Jun. 18, 2013 5.75% Series A Convertible Perpetual Preferred Stock	Dec. 31, 2013 5.75% Series A Convertible Perpetual Preferred Stock item	Jun. 30, 2013 5.75% Series A Convertible Perpetual Preferred Stock
Preferred stock and stockholders' equity
Shares issued						41,900,000																			4,444.4511						43,700,000	73,300,000													345,000
Proceeds from the offering of common stock	$ 222,870,000	$ 452,039,000																													$ 215,200,000	$ 275,000,000
Dividend rate (as a percent)	5.75%	5.75%																							8.00%																					5.75%
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001						$ 0.0001																	$ 0.0001
Number of shares of common stock to be issued upon conversion																																					10,000		108,800,000	108,800,000	10,000					162.4431
Share price (in dollars per share)						$ 7.16		$ 6.39						$ 6.26					$ 6.40									$ 90,000						$ 10.99								$ 6.26			$ 1,000
Gross proceeds from preferred stock offering		311,556,000																						400,000,000
Placement agent fees																								14,000,000
Other offering expenses																								500,000
Par value of common stock (in dollars per share)	$ 0.0001	$ 0.0001				$ 0.0001																																$ 0.0001
Preferred stock converted into common stock (in shares)											108,800,000																							44,400,000
Conversion price per share (in dollars per share)																																		$ 9.00	$ 9.00											$ 6.16
Benefit from conversion of stock (in dollars per share)																							$ 1.99
Proceeds from the issuance of the Preferred Stock allocated to additional paid-in capital	88,445,000	88,445,000
Beneficial conversion feature, amortized upon conversion																							88,400,000			87,300,000	1,100,000
Initial amortization period of beneficial conversion feature																							71 months
Retained earnings	(1,506,217,000)	(274,463,000)		(1,090,870,000)	(266,500,000)
Purchase price								1,484,007,000				854,412,000					426,762,000
Cash purchase price								788,769,000	32,713,000	756,056,000		579,497,000	579,497,000				296,139,000	296,139,000
Preferred stock issued																													695,200,000
Proceeds from conversion of shares																																				0
Cash dividends paid	10,745,000																																			0
Preferred stock, conversion price (in dollars per share)																													$ 7.45								$ 7.45			$ 7.45
Liquidation preference per share (in dollars per share)																																															$ 1,000
Number of shares of common stock to be issued upon conversion at initial conversion rate																																														56,000,000
Closing sale price of common stock as minimum percentage of the conversion price to automatically convert preferred stock into common stock																																														150.00%
Minimum number of trading days within 30 consecutive trading days during which the closing sales price of common stock per share must exceed the conversion price for the preferred stocks to be redeemable																																														20
Number of consecutive trading day periods within which the closing sale price of common stock price per share must exceed the conversion price for at least 20 trading days for the preferred stocks to be redeemable																																														30 days
Number of trading days immediately following effective date of fundamental change within which holders will receive specified shares of common stock																																														30
Number of consecutive trading day periods ending on the third business day prior to settlement date																																														5 days
Number of shares of common stock to be issued upon conversion on fundamental change																																														292.3977
Threshold period of dividends in arrears and unpaid which will give holders of the Convertible Preferred Stock voting rights																																														18 months
Number of additional directors that can be appointed by holders of the Convertible Preferred Stock until arrearage is paid in full																																														2
Authorized shares of common stock, after amendment of certificate of incorporation	670,000,000	336,666,666																														336,700,000	670,000,000
Payment for capital commitment	17,346,000	18,619,000	985,000				6,000,000													600,000												4,000,000
Authorized shares of common stock, before amendment of certificate of incorporation																																33,300,000
Shares issued														16,460,000	4,310,000	20,770,000														10,880												51,344,000	51,300,000	20,800,000
Purchase price	222,870,000	569,000,000				300,000,000
Net proceeds received						294,000,000																																							335,500,000
Payment of cumulative, declared dividends																																														9,100,000
Number of shares issued as non-cash dividend																																														2,000,000
Cumulative, undeclared dividends																																														1,700,000
Increase in shares of common stock authorized																																	333,300,000
Number of shares of common stock that can be purchased from warrants																				36,700,000		1
Exercise price (in dollars per share)																				$ 4.50		$ 8.40
Proceeds from issuance of warrants		43,590,000																		43,600,000
Warrants outstanding																					600,000	1,200,000
Cash Portion (in dollars per share)																						$ 20
Cash exercise price per $1.00 received																						$ 0.82
Gain on expiration of the warrants	$ 1,600,000