Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Commitments And Contingencies Disclosure [Line Items]
Transportation commitments future minimum transportation fees due six months change	$ 775.0
Period of transportation commitments future minimum transportation fees due six months change	25 years
Minimum
Commitments And Contingencies Disclosure [Line Items]
Terms of contingent transportation and gathering contracts	5 years
Transportation and gathering commitments contingent upon construction and modification	25,000
Delivery of natural gas per day	50,000
Period for delivery of natural gas	5 years
Delivery of ethane per day	5,000
Period of delivery of ethane	3 years
Maximum
Commitments And Contingencies Disclosure [Line Items]
Terms of contingent transportation and gathering contracts	20 years
Transportation and gathering commitments contingent upon construction and modification	400,000
Delivery of natural gas per day	80,000
Period for delivery of natural gas	10 years
Delivery of ethane per day	10,000
Period of delivery of ethane	15 years