Income per Common Unit of the Operating Partnership - Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income (Numerator) [Abstract]
Net income available to common shareholders	$ 54,253	$ 91,331	$ 161,434	$ 157,797
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	146,215	148,582	146,121	148,594
Dilutive units for long-term compensation plans	892	594	667	626
Weighted Average Number of Shares Outstanding, Diluted	147,107	149,176	146,788	149,220
Liberty Property Limited Partnership [Member]
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 55,677	$ 93,637	$ 165,684	$ 161,914
Less: Preferred unit distributions	(118)	(118)	(354)	(354)
Net income available to common shareholders	$ 55,559	$ 93,519	$ 165,330	$ 161,560
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	149,751	152,121	149,659	152,134
Dilutive units for long-term compensation plans	892	594	667	626
Weighted Average Number of Shares Outstanding, Diluted	150,643	152,715	150,326	152,760
Liberty Property Limited Partnership [Member] | Common Units [Member]
Earnings Per Unit, Basic [Abstract]
Income per common share - basic	$ 0.37	$ 0.61	$ 1.10	$ 1.06
Earnings Per Unit, Diluted [Abstract]
Income per common share - diluted	$ 0.37	$ 0.61	$ 1.10	$ 1.06