Leases - Additional Information (Detail) (USD $)	3 Months Ended											3 Months Ended
	Mar. 31, 2013 Property State Portfolios	Mar. 31, 2012	Mar. 31, 2013 Marketing Estate [Member] Allowance for Doubtful Accounts [Member]	Mar. 31, 2013 USTs [Member]	Dec. 31, 2012 USTs [Member]	Mar. 31, 2013 Getty Petroleum Marketing [Member] Property	Mar. 31, 2012 Getty Petroleum Marketing [Member] Allowance for Doubtful Accounts [Member]	Mar. 31, 2013 Getty Petroleum Marketing [Member] Allowance for Doubtful Accounts [Member] Rent Receivable [Member]	Mar. 31, 2013 Getty Petroleum Marketing [Member] Allowance for Doubtful Accounts [Member] Real Estate Taxes Receivable [Member]	Jan. 13, 2011 CPD NY Energy Corp. [Member] Station	May 01, 2012 NECG Holdings Corp [Member] Property	Mar. 31, 2013 Maximum [Member] Property	Mar. 31, 2013 Minimum [Member]
Leases [Line Items]
Number of properties leased for other retail purposes												50
Number of properties marketed for sale and which have temporary occupancies	20
Number of properties	1,026
Number of states in which our properties are located	21
Number of properties previously leased to GPMI						660
Allowance for Doubtful Accounts							$ 10,016,000	$ 20,669,000	$ 20,669,000
Recoveries			2,113,000
Number of new triple net leases we've entered into	10
Number of leased properties with new tenants	443
License agreements with occupants properties including Marketing's former sub-tenants	155
Properties which have had their underground storage tanks removed	20
Properties previously subject to the Master Lease that are vacant and marked for sale	40
Number of petroleum distributor property portfolios	10
Number of petroleum lease properties	443
Unitary triple-net lease agreements initial terms													15 years
Unitary triple-net lease agreements successive terms												20 years
Maximum lease commitment for capital expenditure	14,080,000
Amount of asset retirement obligations removed from the balance sheet	11,955,000
Net asset costs related to USTs removed from the balance Sheet				10,173,000	10,173,000
Deferred rental revenue	1,782,000
Lease origination costs	3,472,000
Revenues from rental properties included in continuing operations	23,009,000	26,908,000
Revenues due or received from Marketing under the Master Lease		13,717,000
Real estate taxes paid that are reimbursable by tenants	3,440,000	4,447,000
Revenues realized under interim fuel supply agreements	634,000
Revenue Recognition Adjustments Included in Continuing Operations Increased Rental Revenue	2,383,000	634,000
Investment in direct financing lease	91,685,000
Investments in direct financing lease, minimum lease payments receivable	201,129,000
Investment in direct financing lease, unguaranteed estimated residual value	11,991,000
Investment in direct financing lease, deferred income	$ 121,435,000
Number of Mobil-branded gasoline stations for which a fee or leasehold title was acquired										59
Number of Mobil-branded gasoline stations in which we took a security interest										6
Number of properties for which a triple net lease was entered into											84