Significant Tenant (Details) (Lessee of real estate investments, Travel Centers of America LLC)	9 Months Ended
Sep. 30, 2012
Lessee of real estate investments \| Travel Centers of America LLC
Significant tenant disclosures
Percentage of real estate properties leased	39.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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