Partnership's Repurchase Activities (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended						3 Months Ended		12 Months Ended
	Dec. 31, 2012		Nov. 30, 2012		Oct. 31, 2012		Dec. 31, 2012		Sep. 30, 2012		Jul. 31, 2012
Capital Unit [Line Items]
Total Number of Units Purchased as Part of a Publicly Announced Plan or Program	331		645		39		1,015		22
Average Price Paid per Unit	$ 4.13	[1]	$ 4.20	[1]	$ 4.28	[1]	$ 4.18	[1]	$ 4.26	[1]
Maximum Number of Units that May Yet Be Purchased Under the Program	1,963		2,294		2,939		1,963		2,978		3,000

[1] Amounts include repurchase costs.