Owners' Equity - Operating Partnership(Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	3,808,746	3,928,733
Preferred Units, Total Annual Cash Distributions	$ 21,000,000	$ 21,000,000	$ 21,000,000
Preferred Units, Outstanding	9,740,000	9,740,000
Series B Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	95,000,000
Preferred Units, Outstanding	3,800,000
Redeemable Preferred Units Liquidation Preference	$ 25
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.45%
preferred units redeemable date	Aug. 31, 2009
Redeemable preferred units Exchangeable date	8/31/13 into Series B Cumulative Redeemable Preferred Shares of the Trust
Preferred Units, Annual Cash Distributions	$ 1.86	$ 1.86	$ 1.86
Series E Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.50	$ 3.50	$ 3.50
Series F Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	50,000,000
Preferred Units, Outstanding	1,000,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.33	$ 3.33	$ 3.33
Series G Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.35	$ 3.35	$ 3.35
Series H Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	100,000,000
Preferred Units, Outstanding	4,000,000
Redeemable Preferred Units Liquidation Preference	$ 25
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.40%
preferred units redeemable date	Aug. 21, 2012
Redeemable preferred units Exchangeable date	8/21/17 into Series H Cumulative Redeemable Preferred Shares of the Trust
Preferred Units, Annual Cash Distributions	$ 1.85	$ 1.85	$ 1.85
Liberty Property Limited Partnership [Member]
Limited Partners' Capital Account [Line Items]
Preferred Units, Total Annual Cash Distributions	21,000,000.00	21,000,000.00	21,000,000.00
market value of the outstanding common units	117,600,000
Preferred Units, Outstanding	9,740,000	9,740,000
Liberty Property Limited Partnership [Member] | Series B Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	95,000,000
Preferred Units, Outstanding	3,800,000
Redeemable Preferred Units Liquidation Preference	$ 25
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.45%
preferred units redeemable date	Aug. 31, 2009
Redeemable preferred units Exchangeable date	8/31/13 into Series B Cumulative Redeemable Preferred Shares of the Trust
Preferred Units, Annual Cash Distributions	$ 1.86	$ 1.86	$ 1.86
Liberty Property Limited Partnership [Member] | Series E Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.50	$ 3.50	$ 3.50
Liberty Property Limited Partnership [Member] | Series F Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	50,000,000
Preferred Units, Outstanding	1,000,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.33	$ 3.33	$ 3.33
Liberty Property Limited Partnership [Member] | Series G Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
Redeemable Preferred Units Liquidation Preference	$ 50
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	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
Preferred Units, Annual Cash Distributions	$ 3.35	$ 3.35	$ 3.35
Liberty Property Limited Partnership [Member] | Series H Preferred Stock [Member]
Limited Partners' Capital Account [Line Items]
Noncontrolling Interest in Operating Partnerships	100,000,000
Preferred Units, Outstanding	4,000,000
Redeemable Preferred Units Liquidation Preference	$ 25
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.40%
preferred units redeemable date	Aug. 21, 2012
Redeemable preferred units Exchangeable date	8/21/17 into Series H Cumulative Redeemable Preferred Shares of the Trust
Preferred Units, Annual Cash Distributions	$ 1.85	$ 1.85	$ 1.85
Conversion Ratio of Preferred Units to Preferred Shares [Member] [Member]
Limited Partners' Capital Account [Line Items]
Preferred Unit, Convertible to Preferred Shares	1
Preferred Shares, Converted from Common Unit	1
Conversion Ratio of Preferred Units to Preferred Shares [Member] [Member] | Liberty Property Limited Partnership [Member]
Limited Partners' Capital Account [Line Items]
Preferred Unit, Convertible to Preferred Shares	1
Preferred Shares, Converted from Common Unit	1
Common Stock [Member] | Continuous Equity Offering [Member] | Liberty Property Limited Partnership [Member]
Limited Partners' Capital Account [Line Items]
Common Units Issued During Period			12,800,000
Common Units Issued During Period, Value			$ 283,200,000