Income per Common Unit of the Operating Partnership (Tables)

12 Months Ended

Dec. 31, 2011

Income Per Common Unit [Line Items]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	2011					2010
	Income (Numerator)		Weighted Average Shares (Denominator)	Per Share		Income (Numerator)		Weighted Average Shares (Denominator)	Per Share
Basic income from continuing operations
Income from continuing operations net of noncontrolling interest	$	115,469	114,755	$	1.00	$	105,172	112,924	$	0.93
Dilutive shares for long-term compensation plans	—		748			—		682
Diluted income from continuing operations
Income from continuing operations net of noncontrolling interest	115,469		115,503	$	1.00	105,172		113,606	$	0.92
Basic income from discontinued operations
Discontinued operations net of noncontrolling interest	68,530		114,755	$	0.60	22,590		112,924	$	0.20
Dilutive shares for long-term compensation plans	—		748			—		682
Diluted income from discontinued operations
Discontinued operations net of noncontrolling interest	68,530		115,503	$	0.59	22,590		113,606	$	0.20
Basic income per common share
Net income available to common shareholders	183,999		114,755	$	1.60	127,762		112,924	$	1.13
Dilutive shares for long-term compensation plans	—		748			—		682
Diluted income per common share
Net income available to common shareholders	$	183,999	115,503	$	1.59	$	127,762	113,606	$	1.12

	2009
	Income (Numerator)		Weighted Average Shares (Denominator)	Per Share
Basic income from continuing operations
Income from continuing operations net of noncontrolling interest	$	9,623	107,550	$	0.09
Dilutive shares for long-term compensation plans	—		452
Diluted income from continuing operations
Income from continuing operations net of noncontrolling interest	9,623		108,002	$	0.09
Basic income from discontinued operations
Discontinued operations net of noncontrolling interest	46,753		107,550	$	0.43
Dilutive shares for long-term compensation plans	—		452
Diluted income from discontinued operations
Discontinued operations net of noncontrolling interest	46,753		108,002	$	0.43
Basic income per common share
Net income available to common shareholders	56,376		107,550	$	0.52
Dilutive shares for long-term compensation plans	—		452
Diluted income per common share
Net income available to common shareholders	$	56,376	108,002	$	0.52

Liberty Property Limited Partnership [Member]

Income Per Common Unit [Line Items]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	2011						2010
	Income (Numerator)			Weighted Average Units (Denominator)	Per Unit		Income (Numerator)			Weighted Average Units (Denominator)	Per Unit
Income from continuing operations net of noncontrolling interest	$	140,382					$	129,837
Less: Preferred unit distributions	(21,069		)				(21,012		)
Basic income from continuing operations
Income from continuing operations available to common unitholders	119,313			118,624	$	1.00	108,825			116,871	$	0.93
Dilutive units for long-term compensation plans	—			748			—			682
Diluted income from continuing operations
Income from continuing operations available to common unitholders	119,313			119,372	$	1.00	108,825			117,553	$	0.92
Basic income from discontinued operations
Discontinued operations	70,839			118,624	$	0.60	23,373			116,871	$	0.20
Dilutive units for long-term compensation plans	—			748			—			682
Diluted income from discontinued operations
Discontinued operations	70,839			119,372	$	0.59	23,373			117,553	$	0.20
Basic income per common unit
Income available to common unitholders	190,152			118,624	$	1.60	132,198			116,871	$	1.13
Dilutive units for long-term compensation plans	—			748			—			682
Diluted income per common unit
Income available to common unitholders	$	190,152		119,372	$	1.59	$	132,198		117,553	$	1.12

	2009
	Income (Numerator)			Weighted Average Units (Denominator)	Per Unit
Income from continuing operations net of noncontrolling interest	$	31,035
Less: Preferred unit distributions	(21,012		)
Basic income from continuing operations
Income from continuing operations available to common unitholders	10,023			111,568	$	0.09
Dilutive units for long-term compensation plans	—			452
Diluted income from continuing operations
Income from continuing operations available to common unitholders	10,023			112,020	$	0.09
Basic income from discontinued operations
Discontinued operations	48,466			111,568	$	0.43
Dilutive units for long-term compensation plans	—			452
Diluted income from discontinued operations
Discontinued operations	48,466			112,020	$	0.43
Basic income per common unit
Income available to common unitholders	58,489			111,568	$	0.52
Dilutive units for long-term compensation plans	—			452
Diluted income per common unit
Income available to common unitholders	$	58,489		112,020	$	0.52