Related Party Transactions - Midland Leases (Details) (Midland, Texas [Member], Wexford Affiliate [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 02, 2014	Oct. 02, 2013	Aug. 02, 2013	Jul. 31, 2013
Corporate Office Space [Member]
Related Party Transaction
Term of lease from related party	5 years
Office rent to affiliate	$ 435	$ 214	$ 155
Monthly rent				53	25	15	13
Annual monthly rent increase	4.00%
Field Office Space [Member]
Related Party Transaction
Term of lease from related party	4 years
Office rent to affiliate	129
Bison [Member] | Field Office Space [Member]
Related Party Transaction
Monthly rent	$ 11
Annual monthly rent increase	3.00%