Consolidated Statement of Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Accumulated Distributions in Excess of Net Income [Member]	Parent [Member]	Noncontrolling interest operating partnership Common [Member]	Noncontrolling interest-consolidated joint ventures [Member]	Liberty Property Limited Partnership [Member]	Liberty Property Limited Partnership [Member] General Partner [Member]	Liberty Property Limited Partnership [Member] Limited Partner [Member]	Liberty Property Limited Partnership [Member] Noncontrolling interest-consolidated joint ventures [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive loss - foreign currency translation	$ (6,229,000)								$ (6,229,000)
Other comprehensive loss - derivative instruments	(1,539,000)								(1,539,000)
Beginning Balance at Dec. 31, 2015	3,009,947,000	$ 148,000	$ 3,669,627,000	$ (17,893,000)	$ (698,954,000)	$ 2,952,928,000	$ 53,100,000	$ 3,919,000	3,009,947,000	$ 2,952,928,000	$ 53,100,000	$ 3,919,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from the issuance of common shares	11,967,000	0	11,967,000	0	0	11,967,000	0	0
Net income	165,500,000	0	0	0	161,434,000	161,434,000	3,896,000	170,000	165,500,000	161,434,000	3,896,000	170,000
Contributions from partners									25,788,000	25,788,000
Distributions	(214,225,000)	0	0	0	(209,010,000)	(209,010,000)	(5,045,000)	(170,000)
Distributions to partners									(214,225,000)	(209,010,000)	(5,045,000)	(170,000)
Share/Unit repurchase	(40,896,000)	(1,000)	(40,895,000)	0	0	(40,896,000)	0	0	(40,896,000)	(40,896,000)
Share-based compensation	13,821,000	0	13,821,000	0	0	13,821,000	0	0
Other comprehensive loss - foreign currency translation	(23,003,000)	0	0	(22,460,000)	0	(22,460,000)	(543,000)	0	(23,003,000)	(22,460,000)	(543,000)
Other comprehensive loss - derivative instruments	(1,132,000)	0	0	(1,106,000)	0	(1,106,000)	(26,000)	0	(1,132,000)	(1,106,000)	(26,000)
Redemption of noncontrolling interests - common units	0	0	132,000	0	0	132,000	(132,000)	0	0	132,000	(132,000)
Ending Balance at Sep. 30, 2016	2,921,979,000	$ 147,000	$ 3,654,652,000	$ (41,459,000)	$ (746,530,000)	$ 2,866,810,000	$ 51,250,000	$ 3,919,000	2,921,979,000	$ 2,866,810,000	$ 51,250,000	$ 3,919,000
Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance at Dec. 31, 2015	7,537,000								7,537,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (Mezzanine)	354,000								354,000
Distributions (Mezzanine)	(354,000)								(354,000)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2016	$ 7,537,000								$ 7,537,000