DERIVATIVE INSTRUMENTS (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Commodity derivatives:
Realized gains	$ (1,145)	$ (26,242)	$ (9,688)	$ (78,637)
Unrealized losses	6,678	50,231	9,016	41,659
Interest rate derivatives:
Realized gains	0	(2,758)	(12,885)	(8,479)
Unrealized losses	0	1,564	13,060	4,713
Realized and unrealized losses (gains) on derivative instruments, net	$ 5,533	$ 22,795	$ (497)	$ (40,744)