Income per Common Unit of the Operations Partnership - Options Exercised (Details) - shares	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Liberty Property Limited Partnership \| Stock Option \| Common Units
Stock Option Exercises [Line Items]
Amount of options exercised in period	109,000	151,000

Number of share options (or share units) exercised during the current period.

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Name:	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration