Related Party Transactions - Additional Information (Detail) (General Partner)	9 Months Ended
	Sep. 30, 2012
Related Party Transaction [Line Items]
Percentage of cash distributions from operations as incentive management fee	4.00%
Operating Leases
Related Party Transaction [Line Items]
Equipment management fees as percentage of gross revenues	3.50%
Full Payout Leases
Related Party Transaction [Line Items]
Equipment management fees as percentage of gross revenues	2.00%