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, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income (Numerator) [Abstract]
Net income available to common shareholders	$ 49,627	$ 35,513	$ 107,181	$ 66,464
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	145,995	148,778	146,002	148,574
Dilutive units for long-term compensation plans	740	676	620	673
Weighted Average Number of Shares Outstanding, Diluted	146,735	149,454	146,622	149,247
Liberty Property Limited Partnership [Member]
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 50,944	$ 36,471	$ 110,007	$ 68,275
Less: Preferred unit distributions	(118)	(118)	(236)	(236)
Net income available to common shareholders	$ 50,826	$ 36,353	$ 109,771	$ 68,039
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	149,534	152,317	149,541	152,114
Dilutive units for long-term compensation plans	740	676	620	673
Weighted Average Number of Shares Outstanding, Diluted	150,274	152,993	150,161	152,787
Liberty Property Limited Partnership [Member] | Common Units [Member]
Earnings Per Unit, Basic [Abstract]
Income per common share - basic	$ 0.34	$ 0.24	$ 0.73	$ 0.45
Earnings Per Unit, Diluted [Abstract]
Income per common share - diluted	$ 0.34	$ 0.24	$ 0.73	$ 0.45