Organization and Description of Business (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Organization and Description of Business
Number of property owned	121
Number of states in which the entity owned properties	29
Rentable area of property (in square foot)	20,400,000
Number of warehouse/distribution properties	71
Number of manufacturing properties	30
Number of flex/office properties	20
Percentage of properties leased to tenants	95.70%
Number of tenants to whom properties are given on lease	104
STAG Industrial Operating Partnership, L.P.
Organization and Description of Business
Ownership interest in Operating Partnership (as a percent)	77.15%	67.12%