Common Unit Repurchase and Retirement - Additional Information (Detail) - USD ($) shares in Thousands		1 Months Ended			3 Months Ended			67 Months Ended
	Jul. 30, 2015	Jun. 30, 2018	May 31, 2018	Apr. 30, 2018	Jun. 30, 2018	Mar. 31, 2018		Jan. 31, 2018	Feb. 28, 2018	Dec. 31, 2017	Sep. 30, 2017
Capital Unit [Line Items]
Company's common units authorized for repurchase								2,200	5,500
Third Amendment
Capital Unit [Line Items]
Availability required to repurchase common units	$ 45,000,000
Percentage of the maximum facility size on a historical proforma and forward-looking basis	15.00%
Non Seasonal maximum borrowing capacity under revolving credit facility	$ 300,000,000
Minimum fixed charge coverage ratio for distributions to unit holders or to repurchase common units	115.00%
Plan III Common Units Repurchase Program
Capital Unit [Line Items]
Company's common units repurchased and retired		261	202	626	1,089	1,281		2,700
Company's common units authorized for repurchase								2,200	5,500
Total Common Units remain available for repurchase		3,130	3,391	3,593	3,130	4,219	[1]			2,207	2,207
Common Stock Available for Repurchase Under Open Market Transactions
Capital Unit [Line Items]
Company's common units authorized for repurchase									3,000
Common Stock Available for Repurchase Under Privately Negotiated Transactions
Capital Unit [Line Items]
Company's common units authorized for repurchase									2,500

[1] In February 2018, the Board authorized an increase in the number of Common Units available for repurchase from 2.2 million to 5.5 million.