Summarized Financial Information for Reportable Segments (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]
Capital expenditures	$ 269,631		$ 270,954
Marcellus
Segment Reporting Information [Line Items]
Capital expenditures	6,455	[1]	184	[2]
Marcellus | Investments In Unconsolidated Affiliates
Segment Reporting Information [Line Items]
Capital expenditures	33,200		93,200
Niobrara
Segment Reporting Information [Line Items]
Capital expenditures	30,658	[3]	11,526	[4]
Niobrara | Attributable to Noncontrolling Interest Owners
Segment Reporting Information [Line Items]
Capital expenditures	16,000		5,800
Utica
Segment Reporting Information [Line Items]
Capital expenditures	95,638	[5]	65,756	[6]
Utica | Investments In Unconsolidated Affiliates
Segment Reporting Information [Line Items]
Capital expenditures	76,200		72,000
Utica | Attributable to Noncontrolling Interest Owners
Segment Reporting Information [Line Items]
Capital expenditures	30,900		22,000
Mid-Continent
Segment Reporting Information [Line Items]
Capital expenditures	17,022		38,996	[7]
Mid-Continent | Investments In Unconsolidated Affiliates
Segment Reporting Information [Line Items]
Capital expenditures			$ 300

[1] Amount excludes $33.2 million for the Partnership’s share of capital expenditures included in investments in unconsolidated affiliates.

[2] Amount excludes $93.2 million for the Partnership’s share of capital expenditures included in investments in unconsolidated affiliates.

[3] Amount includes $16.0 million of capital expenditures attributable to noncontrolling interest owners.

[4] Amount includes $5.8 million of capital expenditures attributable to noncontrolling interest owners.

[5] Amount excludes $76.2 million for the Partnership’s share of capital expenditures included in investments in unconsolidated affiliates and includes $30.9 million of capital expenditures attributable to noncontrolling interest owners.

[6] Amount excludes $72.0 million for the Partnership’s share of capital expenditures included in investments in unconsolidated affiliates and includes $22.0 million of capital expenditures attributable to noncontrolling interest owners.

[7] Amount excludes $0.3 million for the Partnership’s share of capital expenditures included in investments in unconsolidated affiliates.