Income per Common Unit of the Operating Partnership - Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 39,887	$ 39,574
Income from discontinued operations	14,786	103,007
Net income available to common shareholders	$ 54,330	$ 140,181
Weighted Average Units (Denominator) [Abstract]
Income from continuing operations net of noncontrolling interest - basic, weighted average shares (in shares)	147,559	147,060
Dilutive units for long-term compensation plans	981	813
Income from continuing operations net of noncontrolling interest - diluted, weighted average shares (in shares)	148,540	147,873
Liberty Property Limited Partnership
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 40,918	$ 40,631
Income from continuing operations available to common unitholders	40,834	40,513
Income from discontinued operations	14,786	103,007
Net income available to common shareholders	$ 55,620	$ 143,520
Weighted Average Units (Denominator) [Abstract]
Income from continuing operations net of noncontrolling interest - basic, weighted average shares (in shares)	151,079	150,580
Dilutive units for long-term compensation plans	981	813
Income from continuing operations net of noncontrolling interest - diluted, weighted average shares (in shares)	152,060	151,393
Liberty Property Limited Partnership | Common Units
Earnings Per Unit, Basic [Abstract]
Income from continuing operations (in usd per share)	$ 0.27	$ 0.27
Income from discontinued operations (in usd per share)	0.10	0.68
Income per common share or unit - basic (in usd per share)	0.37	0.95
Earnings Per Unit, Diluted [Abstract]
Income from continuing operations (in usd per share)	0.27	0.27
Income from discontinued operations (in usd per share)	0.10	0.68
Income per common share or unit - diluted (in usd per share)	$ 0.37	$ 0.95