Organization And Basis Of Presentation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended						12 Months Ended									1 Months Ended			12 Months Ended	1 Months Ended	12 Months Ended
	May 14, 2012	Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Sep. 30, 2012 Segment Subsidiaries	Sep. 30, 2012 Stagecoach ft3 mi in	Sep. 30, 2012 Marc I Pipeline MMcf in	Sep. 30, 2012 Thomas Corners ft3	Sep. 30, 2012 Steuben ft3	Sep. 30, 2012 Seneca Lake ft3	Sep. 30, 2012 Bath MMBbls	Sep. 30, 2012 Stagecoach North And South Laterals MMcf	Sep. 30, 2012 New York mi in	Nov. 25, 2011 US Salt LLC And Tres Palacios Gas Storage LLC	Dec. 21, 2011 Public Owned Common Units	Dec. 21, 2011 Inergy Owned Common Units	Sep. 30, 2012 Inergy Owned Common Units	May 14, 2012 US Salt, LLC	Sep. 30, 2012 Salt Products Segment	Sep. 30, 2012 Incentive distribution rights
Partnership Organization And Basis Of Presentation [Line Items]
Limited partnership interest																	100.00%	24.80%	75.20%	75.00%	100.00%
Number of Subsidiaries								2
Common stock, issued								18,400,000
Common stock, issued under the underwriters overallotment rights								2,400,000
Percentage of distribution entitled to receive								50.00%
Initial quarterly distribution per unit		$ 0.38	[1]	$ 0.37	[1]	$ 0.04	[1]	$ 0.37															$ 0.37
Distributions declared greater than initial annualized distribution per share		$ 0.015		$ 0.01
Annualized distribution amount		$ 1.2		$ 0.7
Number of Reportable Segments								2
Number of Major Entities in Industry																						5
Number of Operating Segments								2,000,000
Capacity of natural gas storage facility									26,300,000,000		7,000,000,000	6,200,000,000	1,500,000,000	1,500,000
Capacity Of transportation service										450					325
Length of natural gas pipeline									39							37.5
Diameter of natural gas pipeline									30	30						12
Membership interests	100.00%
Effective date of acquisition	May 14, 2012

[1] The $0.04 cash distribution per limited partner unit corresponds to an initial quarterly cash distribution of $0.37 per quarter ($1.48 annually) and represents the prorated distribution for the period of time from December 21, 2011, the closing of the Company's initial public offering, through December 31, 2011, the end of the first fiscal quarter.