Income per Common Unit of the Operating Partnership - Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income (Numerator) [Abstract]
Net income available to common shareholders	$ 51,411	$ 49,627	$ 94,443	$ 107,181
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	146,688	145,995	146,602	146,002
Dilutive units for long-term compensation plans	820	740	753	620
Weighted Average Number of Shares Outstanding, Diluted	147,508	146,735	147,355	146,622
Liberty Property Limited Partnership [Member]
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 52,761	$ 50,944	$ 96,942	$ 110,007
Less: Preferred unit distributions	(118)	(118)	(236)	(236)
Net income available to common shareholders	$ 52,643	$ 50,826	$ 96,706	$ 109,771
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	150,216	149,534	150,130	149,541
Dilutive units for long-term compensation plans	820	740	753	620
Weighted Average Number of Shares Outstanding, Diluted	151,036	150,274	150,883	150,161
Liberty Property Limited Partnership [Member] | Common Units [Member]
Earnings Per Unit, Basic [Abstract]
Income per common share - basic	$ 0.35	$ 0.34	$ 0.64	$ 0.73
Earnings Per Unit, Diluted [Abstract]
Income per common share - diluted	$ 0.35	$ 0.34	$ 0.64	$ 0.73