Subsequent Events - Additional Information - IPO (Detail) (USD $)	9 Months Ended		0 Months Ended							0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Oct. 15, 2014 Subsequent Event [Member]	Oct. 08, 2014 Subsequent Event [Member]	Oct. 08, 2014 Subsequent Event [Member] Parent Company [Member]	Oct. 15, 2014 Subsequent Event [Member] Parent [Member]	Oct. 15, 2014 Subsequent Event [Member] Subsidiary of Common Parent [Member] Capital Contributions [Member]	Oct. 15, 2014 Subsequent Event [Member] IPO [Member]	Oct. 08, 2014 Subsequent Event [Member] IPO [Member]	Oct. 15, 2014 Subsequent Event [Member] Common Units [Member]	Oct. 15, 2014 Subsequent Event [Member] Subordinated Units [Member]
Subsequent Event [Line Items]
Initial public offering, shares									9,120,000
Price per common unit									$ 17.00
Common unit, shares					1,093,545
Subordinated unit, shares					10,463,545
Aggregate percentage of limited partner interest in partnership				54.10%	54.10%			42.70%		5.10%	49.00%
General partnership interest and incentive distribution rights			2.00%	2.00%	2.00%
Proceeds from offering				$ 145,000,000
Borrowings under term loan facility				100,000,000		100,000,000
Cash distribution paid				99,200,000
Fees and expenses related to offering				7,500,000
Repayment of debt				97,800,000
Payment of fees and expenses				3,700,000
Cash retained for general partnership purposes	31,047,000	22,501,000		36,800,000
Number of general partner units issued			427,083
Assumed debt						30,000,000
Proceeds from initial public offering								155,000,000
Underwriters discount								9,100,000
Capital contribution paid to Opco							$ 105,500,000