Leases (Details) (USD $)	1 Months Ended		3 Months Ended				6 Months Ended			3 Months Ended			6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012 Property	May 31, 2012	Jun. 30, 2012 Property	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Jun. 30, 2012 Property	Jun. 30, 2011	Jun. 30, 2012 Underground Storage Tanks [Member]	Jun. 30, 2012 Allowance for Doubtful Accounts [Member]	Mar. 31, 2012 Allowance for Doubtful Accounts [Member]	Dec. 31, 2011 Allowance for Doubtful Accounts [Member]	Jun. 30, 2012 Minimum [Member]	Jun. 30, 2012 Maximum [Member]	Jun. 30, 2012 Marketing Leases [Member]	Jun. 30, 2011 Marketing Leases [Member]	Jun. 30, 2012 Marketing Leases [Member]	Jun. 30, 2011 Marketing Leases [Member]	Jun. 30, 2012 Master Lease [Member] Property
Lease (Textual) [Abstract]
Number of properties	1,128		1,128				1,128												775
Real estate tax payments for properties leased																	$ 12,000,000	$ 308,000
Real estate taxes paid related to the portfolio previously leased to Marketing															1,246,000	148,000	4,272,000
Unitary triple-net lease agreements initial terms													15 years
Unitary triple-net lease agreements successive terms														20 years
Bad debt reserve										6,205,000	10,016,000	8,802,000
Net asset costs related to USTs removed from the Balance Sheet									6,203,000
Lease (Additional Textual) [Abstract]
Bad debt reserves for all outstanding rent and real estate tax obligations	25,023,000		25,023,000				25,023,000
Number of separate property portfolios under long-term triple-net leases with petroleum distributors	6		6				6
Number of leased properties with new tenants							282
License agreements with occupants properties including Marketing's former sub-tenants							330
Properties which have had their underground storage tanks removed							70
Properties previously subject to the Master Lease that are vacant and marked for sale							90
Amount of asset retirement obligations removed from the balance sheet							6,875,000
Deferred rental revenue	672,000		672,000				672,000
Future contractual minimum annual rentals receivable One year	7,691,000		7,691,000				7,691,000
Future contractual minimum annual rentals receivable two year	13,694,000		13,694,000				13,694,000
Future contractual minimum annual rentals receivable three year	14,568,000		14,568,000				14,568,000
Future contractual minimum annual rentals receivable four year	14,960,000		14,960,000				14,960,000
Future contractual minimum annual rentals receivable five year	15,106,000		15,106,000				15,106,000
Future contractual minimum annual rentals receivable thereafter	162,858,000		162,858,000				162,858,000
Revenues from rental properties included in continuing operations			26,775,000				57,832,000
Revenues due or received from Marketing under the Master Lease			6,156,000				23,950,000
Revenues related to properties repositioned	30,761,000	18,132,000
Real estate taxes paid that were reimbursed by tenant			2,997,000			681,000	7,444,000	1,600,000
Revenues realized under interim fuel supply agreements							1,586,000
Increase rental revenue			901,000			760,000	1,535,000	975,000
Gross deferred receivable attributable to the Master Lease with Marketing that was fully reserved				25,630,000
Non-cash allowances for deferred rental revenue				19,758,000	19,758,000
Investment in direct financing lease	92,290,000		92,290,000				92,290,000
Investments in direct financing lease, minimum lease payments receivable	209,304,000		209,304,000				209,304,000
Investment in direct financing lease, unguaranteed estimated residual value	11,991,000		11,991,000				11,991,000
Investment in direct financing lease, deferred income	$ 129,005,000		$ 129,005,000				$ 129,005,000
Number of properties leased for other retail purposes	20		20				20
Number of properties marketed for sale and which have temporary occupancies							134