Consolidated Statements of Operations (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net gain on property dispositions included in discontinued operation	$ 4,095,000	$ 221,000	$ 54,722,000	$ 5,491,000
Liberty Property Limited Partnership [Member]
Net gain on property dispositions included in discontinued operation	$ 4,095,000	$ 221,000	$ 54,722,000	$ 5,491,000