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Income per Common Unit of the Operating Partnership Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions		1 Months Ended	9 Months Ended
	Oct. 12, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Subsequent Event [Line Items]
Loss on debt extinguishment			$ (7,618)	$ 0
Subsequent Event [Member]
Subsequent Event [Line Items]
Loss on debt extinguishment	$ (9,000)
Unsecured Notes \| Subsequent Event [Member]
Subsequent Event [Line Items]
Repayments of unsecured notes	$ 350,000
Interest Rate	4.75%
Liberty Property Limited Partnership
Subsequent Event [Line Items]
Loss on debt extinguishment			$ (7,618)	$ 0
Liberty Property Limited Partnership \| Subsequent Event [Member]
Subsequent Event [Line Items]
Loss on debt extinguishment	$ (9,000)
Liberty Property Limited Partnership \| Unsecured Notes \| Subsequent Event [Member]
Subsequent Event [Line Items]
Repayments of unsecured notes	$ 350,000
Interest Rate	4.75%
Common Units \| Liberty Property Limited Partnership
Subsequent Event [Line Items]
Shares, Issued		9.2	9.2
Shares Issued, Price Per Share		$ 50.50	$ 50.50
Proceeds from Issuance of Units		$ 447,900