Sale of Assets (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Mar. 31, 2014	Feb. 28, 2014	Dec. 31, 2013	Apr. 30, 2013 acre
Sale Of Assets [Line Items]
Net proceeds from sale of interest in wells and related leasehold interest	$ 71.0		$ 34.5	$ 6.8
Escrow Deposits Related to Property Sales	6.8
Proceeds from sale of property in Ward County, Texas		5.1
Percentage of assets contributed in limited partnership				5.00%
Percentage of assets of limited partnership purchased from Clayton Williams Energy Inc.				95.00%
Value of assets of limited partnership purchased from Clayton Williams Energy Inc.				215.2
Sale of interest in wells, percent				75.00%
Sale of interest in net undeveloped land, acres				12,000
General Partner
Sale Of Assets [Line Items]
Percent of interest in limited partnership				5.00%
GE Energy Financial Services | Limited Partner
Sale Of Assets [Line Items]
Payments to acquire interest in limited partnership				$ 215.2
Limited partner ownership interest				95.00%