Income per Common Unit of the Operating Partnership - Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Income (Numerator) [Abstract]
Net income available to common shareholders	$ 57,554	$ 30,951
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	146,071	148,315
Dilutive units for long-term compensation plans	460	716
Weighted Average Number of Shares Outstanding, Diluted	146,531	149,031
Liberty Property Limited Partnership [Member]
Income (Numerator) [Abstract]
Income from continuing operations net of noncontrolling interest - consolidated joint ventures	$ 59,063	$ 31,804
Less: Preferred unit distributions	(118)	(118)
Net income available to common shareholders	$ 58,945	$ 31,686
Weighted Average Units (Denominator) [Abstract]
Weighted Average Number of Shares Outstanding, Basic	149,610	151,856
Dilutive units for long-term compensation plans	460	716
Weighted Average Number of Shares Outstanding, Diluted	150,070	152,572
Liberty Property Limited Partnership [Member] \| Common Units [Member]
Earnings Per Unit, Basic [Abstract]
Income per common share - basic	$ 0.39	$ 0.21
Earnings Per Unit, Diluted [Abstract]
Income per common share - diluted	$ 0.39	$ 0.21

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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