Owners' Equity - Operating Partnership(Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Outstanding	0
Preferred Stock Redemption Discount			$ 3,689,000
Preferred Stock Redemption Premium		1,236,000
Preferred Units, Total Annual Cash Distributions		1,600,000.0	9,900,000.0
Continuous Equity Offering [Abstract]
Common stock, Continuous equity offering program, Max amount of equity	200,000,000
Proceeds from Issuance of Common Stock	58,473,000	969,468,000	58,710,000
Series B Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 0	$ 0.45
Stock Redeemed or Called During Period, Value			95,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount			7.45%
Series E Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 1.21	$ 3.50
Stock Redeemed or Called During Period, Value		20,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		7.00%
Series F Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Payments for Repurchase of Preferred Stock and Preference Stock			26,000,000
Preferred Units, Annual Cash Distributions		$ 1.32	$ 1.43
Stock Redeemed or Called During Period, Value		17,500,000	32,500,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		6.65%	6.65%
Series G Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 1.33	$ 3.35
Stock Redeemed or Called During Period, Value		27,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		6.70%
Series H Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 0	$ 0.77
Stock Redeemed or Called During Period, Value			100,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount			7.40%
Treasury Stock [Member]
Limited Partners' Capital Account [Line Items]
Treasury Stock, Shares, Acquired	0	0	0
Common Stock [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units, Sale of Units	0	0	0
Continuous Equity Offering [Abstract]
Number of common shares issued	0	1,900,000	0
Proceeds from Issuance of Common Stock		75,000,000
Liberty Property Limited Partnership [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' units outstanding	3,553,566	3,556,566
market value of the outstanding common units	133,700,000
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Outstanding	0
Preferred Stock Redemption Discount	0		3,689,000
Preferred Stock Redemption Premium	0	1,236,000
Preferred Units, Total Annual Cash Distributions		1,600,000	9,900,000
Liberty Property Limited Partnership [Member] | Continuous Equity Offering [Member]
Continuous Equity Offering [Abstract]
Common stock, Continuous equity offering program, Max amount of equity	200,000,000
Liberty Property Limited Partnership [Member] | Series B Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 0	$ 0.45
Stock Redeemed or Called During Period, Value			95,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount			7.45%
Liberty Property Limited Partnership [Member] | Series E Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 1.21	$ 3.50
Stock Redeemed or Called During Period, Value		20,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		7.00%
Liberty Property Limited Partnership [Member] | Series F Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Payments for Repurchase of Preferred Stock and Preference Stock			26,000,000
Preferred Units, Annual Cash Distributions		$ 1.32	$ 1.43
Stock Redeemed or Called During Period, Value		17,500,000	32,500,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		6.65%	6.65%
Liberty Property Limited Partnership [Member] | Series G Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 1.33	$ 3.35
Stock Redeemed or Called During Period, Value		27,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount		6.70%
Liberty Property Limited Partnership [Member] | Series H Preferred Stock [Member]
Preferred Units Description and Other Disclosures [Abstract]
Preferred Units, Annual Cash Distributions		$ 0	$ 0.77
Stock Redeemed or Called During Period, Value			100,000,000
Preferred Stock Dividends Rate Percentage Or Per Dollar Amount			7.40%
Liberty Property Limited Partnership [Member] | Common Stock [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units, Sale of Units	0	0	0
Continuous Equity Offering [Abstract]
Number of common shares issued	0		0
Liberty Property Limited Partnership [Member] | Common Stock [Member] | Continuous Equity Offering [Member]
Continuous Equity Offering [Abstract]
Number of common shares issued		1,900,000
Proceeds from Issuance of Common Stock		$ 75,000,000