Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) Fields Customer	Sep. 30, 2014 USD ($) Customer	Sep. 30, 2015 USD ($) Fields Customer Segment	Sep. 30, 2014 USD ($) Customer	Dec. 31, 2014 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable	$ 23,607,000		$ 23,607,000		$ 46,378,000
Pension obligations					1,321,000
Gain on reduction of pension obligations				$ 2,208,000
Depreciation, depletion and amortization	$ 67,172,000	$ 29,983,000	$ 170,245,000	51,967,000
Number of field included in assessment of impairment | Fields	3		3
Impairment of oil and gas properties		$ 4,605,000		$ 4,605,000
Deferred tax liability					97,600,000
Asset retirement obligations credit adjusted discount rates			10.45%	8.96%
Number of operating segment | Segment			1
Prior period adjustment in cash flows				$ 11,800,000
Eclipse I [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage	100.00%		100.00%
Eclipse Resources Ohio LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage	100.00%		100.00%
Eclipse Resources Operating, LLC ("Eclipse Operating") [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage	100.00%		100.00%
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of commodity derivative contracts	$ 25,094,000		$ 25,094,000		19,034,000
Sales Revenue, Net [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	5	2	4	2
Unbilled Revenues [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable	$ 21,300,000		$ 21,300,000		$ 24,100,000
Other property and equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation	500,000	$ 400,000	$ 1,300,000	$ 600,000
Other property and equipment [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, expected lives			5 years
Other property and equipment [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, expected lives			40 years
Unproved Oil And Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of oil and gas properties	1,000,000	500,000	$ 7,100,000	4,200,000
Oil and Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation, depletion and amortization	66,700,000	29,600,000	168,900,000	51,400,000
Proved Oil And Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of oil and gas properties	$ 0	$ 4,600,000	$ 0	$ 4,600,000