Income per Common Unit of the Operating Partnership - Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 48,043	$ 40,204
Income from discontinued operations	94,333	2,896
Net income available to common shareholders	$ 140,181	$ 43,032
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	147,060	146,471
Dilutive units for long-term compensation plans	813	750
Weighted Average Number of Shares Outstanding, Diluted	147,873	147,221
Liberty Property Limited Partnership [Member]
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 49,305	$ 41,285
Less: Preferred unit distributions	(118)	(118)
Income from continuing operations available to common unitholders	49,187	41,167
Income from discontinued operations	94,333	2,896
Net income available to common shareholders	$ 143,520	$ 44,063
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	150,580	150,000
Dilutive units for long-term compensation plans	813	750
Weighted Average Number of Shares Outstanding, Diluted	151,393	150,750
Liberty Property Limited Partnership [Member] | Common Units [Member]
Earnings Per Unit, Basic [Abstract]
Income from continuing operations, per basic share	$ 0.33	$ 0.27
Income from discontinued operations, per basic share	0.62	0.02
Income per common share - basic	0.95	0.29
Earnings Per Unit, Diluted [Abstract]
Income from continuing operations, per diluted share	0.33	0.27
Income from discontinued operations, per diluted share	0.62	0.02
Income per common share - diluted	$ 0.95	$ 0.29