Limited Partners' Equity of the Operating Partnership Limited Partners' Equity of the Operating Partnership - Outstanding Cumulative Redeemable Preferred Stock(Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Preferred Units [Line Items]
Preferred Units, Outstanding	1,290,000	1,290,000
Liberty Property Limited Partnership [Member]
Preferred Units [Line Items]
Preferred Units, Outstanding	1,290,000	1,290,000
Preferred Stock Redemption Premium	$ 0
Series E Preferred Stock [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
Redeemable Preferred Units Liquidation Preference	50
Preferred Stock, Dividend Rate, Percentage	7.00%
preferred units redeemable date	Jun. 16, 2010
Redeemable preferred units Exchangeable date	6/16/15 into Series E Cumulative Redeemable Preferred Shares of the Trust
Series E Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
Redeemable Preferred Units Liquidation Preference	50
Preferred Stock, Dividend Rate, Percentage	7.00%
preferred units redeemable date	Jun. 16, 2010
Redeemable preferred units Exchangeable date	6/16/15 into Series E Cumulative Redeemable Preferred Shares of the Trust
Series F Preferred Stock [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	17,500,000
Preferred Units, Outstanding	350,000
Redeemable Preferred Units Liquidation Preference	50
Preferred Stock, Dividend Rate, Percentage	6.65%
preferred units redeemable date	Jun. 30, 2010
Redeemable preferred units Exchangeable date	12/12/15 into Series F Cumulative Redeemable Preferred Shares of the Trust
Series F Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	17,500,000
Preferred Units, Outstanding	350,000
Redeemable Preferred Units Liquidation Preference	50
Preferred Stock, Dividend Rate, Percentage	6.65%
preferred units redeemable date	Jun. 30, 2010
Redeemable preferred units Exchangeable date	12/12/15 into Series F Cumulative Redeemable Preferred Shares of the Trust
Series G Preferred Stock [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
Redeemable Preferred Units Liquidation Preference	50
Preferred Stock, Dividend Rate, Percentage	6.70%
preferred units redeemable date	Dec. 15, 2011
Redeemable preferred units Exchangeable date	12/15/16 into Series G Cumulative Redeemable Preferred Shares of the Trust
Series G Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Preferred Units [Line Items]
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock, Dividend Rate, Percentage	6.70%
preferred units redeemable date	Dec. 15, 2011
Redeemable preferred units Exchangeable date	12/15/16 into Series G Cumulative Redeemable Preferred Shares of the Trust