ENVIRONMENTAL MATTERS - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2012	Sep. 30, 2012	Dec. 31, 2011 Property	Sep. 30, 2012 site Lease	Sep. 30, 2011	Dec. 31, 2010
Environmental Matters And Other Commitments And Contingencies [Line Items]
Payment for pollution legal liability insurance policy	$ 3,062,000
Pollution legal liability insurance policy duration	10 years
Number of properties for which Marketing would not be able to meet its environmental remediation obligations			246
Accrued Marketing Environmental liabilities			47,874,000
Environmental costs, impairment charges			17,017,000
Number of sites for which title to and obligations for USTs were transferred to new tenants				282
Asset retirement obligations removed from balance sheet		6,875,000		6,875,000
Deferred rental revenue		672,000		672,000
Number of new triple net leases entered into through this quarter				6
Environmental remediation costs, net		52,300,000	57,700,000	52,300,000		14,874,000
Accretion expense				2,250,000	469,000
The amount of credits to Environmental Expenses		211,000		2,859,000
Increase in carrying value of property		729,000		4,420,000
Estimated remaining useful life of underground storage tank for capitalized asset retirement costs				10 years
Capitalized asset retirement costs		28,364,000		28,364,000
Capitalized asset retirement cost [Member]
Environmental Matters And Other Commitments And Contingencies [Line Items]
Depreciation and amortization expense for capitalized asset retirement costs		1,324,000		4,492,000
USTs [Member]
Environmental Matters And Other Commitments And Contingencies [Line Items]
Net asset cost related to USTs removed from the balance sheet		6,203,000		6,203,000
Maximum [Member]
Environmental Matters And Other Commitments And Contingencies [Line Items]
Pollution legal liability insurance policy aggregate limit	$ 50,000,000