SUPPLEMENTAL INFORMATION - NATURAL GAS AND CRUDE OIL PROPERTIES Costs Incurred in Natural Gas and Crude Oil Property Acquisition, Exploration and Development Activities (Unadited) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Proved Properties	[1]	$ 3,561	$ 11,973	$ 28,698
Unproved Properties	[1]	15	45,999	3,390
Development Costs	[2]	552,104	608,176	338,294
Exploratory drilling	[3]	0	0	58,988
Geological and geophysical	[3]	0	1	752
Total Costs Incurred		555,680	666,149	430,122
Cost Incurred to Convert PUDs to PDNP		$ 207,800	$ 125,200	$ 40,100

[1] Property acquisition costs represent costs incurred to purchase, lease or otherwise acquire a property.

[2] Development costs represent costs incurred to gain access to and prepare development well locations for drilling, drill and equip development wells, recomplete wells and provide facilities to extract, treat, gather and store crude oil, natural gas and NGLs. Of these costs incurred for the years ended December 31, 2015, 2014 and 2013, $207.8 million, $125.2 million and $40.1 million, respectively, were incurred to convert proved undeveloped reserves to proved developed reserves from the prior year end.

[3] Exploration costs - represents costs incurred in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing crude oil, natural gas and NGLs.