Net Income per Limited Partnership Unit - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended	1 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Item	Nov. 07, 2013 Subsequent Event [Member]	Nov. 07, 2013 Subsequent Event [Member] Forecast [Member]	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Minimum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Maximum percentage of quarterly distributions out of operating surplus					50.00%
Incentive distribution per limited partner unit (in dollars per unit)						$ 0.6563
Number of participating incentive distribution rights		0
Quarterly dividend declared			$ 7.6	$ 21.6
Quarterly dividend distribution declared (in dollars per unit)	$ 0.5025	$ 1.4325	$ 0.5025	$ 1.4325