Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
OPERATING REVENUE
Rental	$ 140,697,000	$ 145,009,000	$ 418,896,000	$ 440,962,000
Operating expense reimbursement	50,160,000	53,963,000	148,757,000	168,430,000
Total operating revenue	190,857,000	198,972,000	567,653,000	609,392,000
OPERATING EXPENSE
Rental property	26,496,000	31,454,000	79,752,000	98,973,000
Real estate taxes	25,968,000	25,953,000	76,490,000	78,579,000
General and administrative	16,151,000	15,573,000	52,770,000	51,428,000
Depreciation and amortization	46,920,000	55,718,000	154,543,000	171,347,000
Impairment - real estate assets	0	0	0	16,775,000
Total operating expenses	115,535,000	128,698,000	363,555,000	417,102,000
Operating income	75,322,000	70,274,000	204,098,000	192,290,000
OTHER INCOME (EXPENSE)
Interest and other income	3,153,000	4,959,000	12,743,000	17,911,000
Loss on debt extinguishment	(3,494,000)	0	(3,494,000)	0
Interest expense	(29,528,000)	(33,559,000)	(91,071,000)	(103,295,000)
Total other income (expense)	(29,869,000)	(28,600,000)	(81,822,000)	(85,384,000)
Income before gain on property dispositions, income taxes and equity in earnings (loss) of unconsolidated joint ventures	45,453,000	41,674,000	122,276,000	106,906,000
Gain on property dispositions	1,318,000	53,467,000	25,671,000	56,987,000
Income taxes	(80,000)	(599,000)	(1,633,000)	(2,613,000)
Equity in earnings (loss) of unconsolidated joint ventures	9,043,000	(847,000)	19,540,000	805,000
Income from continuing operations	55,734,000	93,695,000	165,854,000	162,085,000
Net income	55,734,000	93,695,000	165,854,000	162,085,000
Noncontrolling interest – operating partnership	(1,424,000)	(2,306,000)	(4,250,000)	(4,117,000)
Noncontrolling interest - consolidated joint ventures	(57,000)	(58,000)	(170,000)	(171,000)
Net income available to common shareholders	54,253,000	91,331,000	161,434,000	157,797,000
Comprehensive income attributable to common shareholders
Net income	55,734,000	93,695,000	165,854,000	162,085,000
Other comprehensive loss - foreign currency translation	(4,407,000)	(7,970,000)	(23,003,000)	(6,229,000)
Other comprehensive gain (loss) - derivative instruments	663,000	(1,220,000)	(1,132,000)	(1,539,000)
Other comprehensive loss	(3,744,000)	(9,190,000)	(24,135,000)	(7,768,000)
Total comprehensive income	51,990,000	84,505,000	141,719,000	154,317,000
Less: comprehensive income attributable to noncontrolling interest	(1,393,000)	(2,148,000)	(3,851,000)	(4,105,000)
Comprehensive income attributable to common shareholders	$ 50,597,000	$ 82,357,000	$ 137,868,000	$ 150,212,000
Weighted average number of common shares outstanding
Basic	146,215	148,582	146,121	148,594
Diluted	147,107	149,176	146,788	149,220
Amounts attributable to common shareholders
Net income available to common shareholders	$ 54,253,000	$ 91,331,000	$ 161,434,000	$ 157,797,000
Liberty Property Limited Partnership [Member]
OPERATING REVENUE
Rental	140,697,000	145,009,000	418,896,000	440,962,000
Operating expense reimbursement	50,160,000	53,963,000	148,757,000	168,430,000
Total operating revenue	190,857,000	198,972,000	567,653,000	609,392,000
OPERATING EXPENSE
Rental property	26,496,000	31,454,000	79,752,000	98,973,000
Real estate taxes	25,968,000	25,953,000	76,490,000	78,579,000
General and administrative	16,151,000	15,573,000	52,770,000	51,428,000
Depreciation and amortization	46,920,000	55,718,000	154,543,000	171,347,000
Impairment - real estate assets			0	16,775,000
Total operating expenses	115,535,000	128,698,000	363,555,000	417,102,000
Operating income	75,322,000	70,274,000	204,098,000	192,290,000
OTHER INCOME (EXPENSE)
Interest and other income	3,153,000	4,959,000	12,743,000	17,911,000
Loss on debt extinguishment	(3,494,000)	0	(3,494,000)	0
Interest expense	(29,528,000)	(33,559,000)	(91,071,000)	(103,295,000)
Total other income (expense)	(29,869,000)	(28,600,000)	(81,822,000)	(85,384,000)
Income before gain on property dispositions, income taxes and equity in earnings (loss) of unconsolidated joint ventures	45,453,000	41,674,000	122,276,000	106,906,000
Gain on property dispositions	1,318,000	53,467,000	25,671,000	56,987,000
Income taxes	(80,000)	(599,000)	(1,633,000)	(2,613,000)
Equity in earnings (loss) of unconsolidated joint ventures	9,043,000	(847,000)	19,540,000	805,000
Net income	55,734,000	93,695,000	165,854,000	162,085,000
Noncontrolling interest - consolidated joint ventures	(57,000)	(58,000)	(170,000)	(171,000)
Preferred unit distributions	(118,000)	(118,000)	(354,000)	(354,000)
Net income available to common shareholders	55,559,000	93,519,000	165,330,000	161,560,000
Comprehensive income attributable to common shareholders
Net income	55,734,000	93,695,000	165,854,000	162,085,000
Other comprehensive loss - foreign currency translation	(4,407,000)	(7,970,000)	(23,003,000)	(6,229,000)
Other comprehensive gain (loss) - derivative instruments	663,000	(1,220,000)	(1,132,000)	(1,539,000)
Other comprehensive loss	(3,744,000)	(9,190,000)	(24,135,000)	(7,768,000)
Total comprehensive income	$ 51,990,000	$ 84,505,000	$ 141,719,000	$ 154,317,000
Weighted average number of common shares outstanding
Basic	149,751	152,121	149,659	152,134
Diluted	150,643	152,715	150,326	152,760
Net income allocated to general partners	$ 54,253,000	$ 91,331,000	$ 161,434,000	$ 157,797,000
Net income allocated to limited partners	1,424,000	2,306,000	4,250,000	4,117,000
Amounts attributable to common shareholders
Income from continuing operations	55,677,000	93,637,000	165,684,000	161,914,000
Net income available to common shareholders	$ 55,559,000	$ 93,519,000	$ 165,330,000	$ 161,560,000
Common shares [Member]
Basic:
Income per common share - basic	$ 0.37	$ 0.61	$ 1.10	$ 1.06
Diluted:
Income per common share - diluted	0.37	0.61	1.10	1.06
Distributions per common share or unit	0.475	0.475	1.425	1.425
Common Units [Member] | Liberty Property Limited Partnership [Member]
Basic:
Income per common share - basic	0.37	0.61	1.10	1.06
Diluted:
Income per common share - diluted	0.37	0.61	1.10	1.06
Distributions per common share or unit	$ 0.475	$ 0.475	$ 1.425	$ 1.425