Income per Common Unit of the Operating Partnership - Unit Repurchase (Details) - 2015 Share Repurchase Program [Member] $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) shares	Jun. 30, 2017 USD ($) shares
Common shares [Member]
Class of Stock [Line Items]
Authorized amount of shares available to be repurchased under a share repurchase plan | $	$ 250	$ 250
Number of units repurchased during period | shares	0	0
Liberty Property Limited Partnership [Member] | Common Units [Member]
Class of Stock [Line Items]
Authorized amount of shares available to be repurchased under a share repurchase plan | $	$ 250	$ 250
Number of units repurchased during period | shares	0	0