Shareholders' Equity - Common and Preferred Units (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Temporary Equity [Line Items]
Preferred Units, Total Annual Cash Distributions	$ 9,900,000	$ 21,000,000	$ 21,000,000
Preferred Units, Outstanding	1,290,000	9,740,000
Noncontrolling Interest Operating Partnership Common Units Outstanding	3,713,851	3,808,746
Redeemable Noncontrolling Interest, Equity, Common, Fair Value	132,900,000
Preferred Stock Redemption Discount	3,689,000
Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Preferred Units, Total Annual Cash Distributions	9,900,000	21,000,000	21,000,000
Preferred Units, Outstanding	1,290,000	9,740,000
Preferred Stock Redemption Discount	3,689,000	0	0
Conversion Ratio of Common Units to Common Shares [Member]
Temporary Equity [Line Items]
Common Unit, Convertible to Common Stock	1
Common Stock, Converted from Common Unit	1
Conversion Ratio of Preferred Units to Preferred Shares [Member] [Member]
Temporary Equity [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]
Temporary Equity [Line Items]
Preferred Unit, Convertible to Preferred Shares	1
Preferred Shares, Converted from Common Unit	1
Common Units [Member]
Temporary Equity [Line Items]
Common Units Issued in Connection with Acquisitions	0	0	0
Series B Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.45%
Preferred Units, Annual Cash Distributions	$ 0.45	$ 1.86	$ 1.86
Stock Redeemed or Called During Period, Value	95,000,000
Series B Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.45%
Preferred Units, Annual Cash Distributions	$ 0.45	$ 1.86	$ 1.86
Stock Redeemed or Called During Period, Value	95,000,000
Series E Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
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 E Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	20,000,000
Preferred Units, Outstanding	400,000
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]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	17,500,000
Preferred Units, Outstanding	350,000
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	$ 1.43	$ 3.33	$ 3.33
Stock Redeemed or Called During Period, Value	32,500,000
Payments for Repurchase of Preferred Stock and Preference Stock	26,000,000
Series F Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	17,500,000
Preferred Units, Outstanding	350,000
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	$ 1.43	$ 3.33	$ 3.33
Stock Redeemed or Called During Period, Value	32,500,000
Payments for Repurchase of Preferred Stock and Preference Stock	26,000,000
Series G Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
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 G Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Redeemable Preferred Units Liquidation Preference	$ 50
Noncontrolling Interest in Operating Partnerships	27,000,000
Preferred Units, Outstanding	540,000
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]
Temporary Equity [Line Items]
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.40%
Preferred Units, Annual Cash Distributions	$ 0.77	$ 1.85	$ 1.85
Stock Redeemed or Called During Period, Value	100,000,000
Series H Preferred Stock [Member] | Liberty Property Limited Partnership [Member]
Temporary Equity [Line Items]
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount	7.40%
Preferred Units, Annual Cash Distributions	$ 0.77	$ 1.85	$ 1.85
Stock Redeemed or Called During Period, Value	$ 100,000,000