Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
OPERATING REVENUE
Rental	$ 124,969	$ 139,143	$ 248,350	$ 278,198
Operating expense reimbursement	39,902	47,511	80,402	98,597
Development service fee income	18,259	0	29,744	0
Total operating revenue	183,130	186,654	358,496	376,795
OPERATING EXPENSE
Rental property	17,716	24,745	37,600	53,255
Real estate taxes	23,244	25,202	46,525	50,522
General and administrative	15,282	15,629	32,224	36,619
Depreciation and amortization	45,789	53,545	91,249	107,623
Development service fee expense	17,828	0	28,832	0
Total operating expenses	119,859	119,121	236,430	248,019
Operating income	63,271	67,533	122,066	128,776
OTHER INCOME (EXPENSE)
Interest and other income	1,928	4,992	3,804	9,590
Interest expense	(21,942)	(30,131)	(44,285)	(61,543)
Total other income (expense)	(20,014)	(25,139)	(40,481)	(51,953)
Income before gain on property dispositions, income taxes and equity in earnings of unconsolidated joint ventures	43,257	42,394	81,585	76,823
Gain on property dispositions	5,895	3,832	6,702	24,353
Income taxes	(324)	(752)	(946)	(1,553)
Equity in earnings of unconsolidated joint ventures	3,990	5,583	9,721	10,497
Income from continuing operations	52,818	51,057	97,062	110,120
Net income	52,818	51,057	97,062	110,120
Noncontrolling interest – operating partnership	(1,350)	(1,317)	(2,499)	(2,826)
Noncontrolling interest - consolidated joint ventures	(57)	(113)	(120)	(113)
Net income available to common shareholders	51,411	49,627	94,443	107,181
Comprehensive income attributable to common shareholders
Net income	52,818	51,057	97,062	110,120
Other comprehensive income (loss) - foreign currency translation	7,503	(13,509)	10,680	(18,596)
Other comprehensive (loss) income - derivative instruments	(38)	(435)	275	(1,795)
Other comprehensive income (loss)	7,465	(13,944)	10,955	(20,391)
Total comprehensive income	60,283	37,113	108,017	89,729
Less: comprehensive income attributable to noncontrolling interest	(1,582)	(1,101)	(2,875)	(2,458)
Comprehensive income attributable to common shareholders	$ 58,701	$ 36,012	$ 105,142	$ 87,271
Weighted average number of common shares outstanding
Basic	146,688	145,995	146,602	146,002
Diluted	147,508	146,735	147,355	146,622
Amounts attributable to common shareholders
Net income available to common shareholders	$ 51,411	$ 49,627	$ 94,443	$ 107,181
Liberty Property Limited Partnership [Member]
OPERATING REVENUE
Rental	124,969	139,143	248,350	278,198
Operating expense reimbursement	39,902	47,511	80,402	98,597
Development service fee income	18,259	0	29,744	0
Total operating revenue	183,130	186,654	358,496	376,795
OPERATING EXPENSE
Rental property	17,716	24,745	37,600	53,255
Real estate taxes	23,244	25,202	46,525	50,522
General and administrative	15,282	15,629	32,224	36,619
Depreciation and amortization	45,789	53,545	91,249	107,623
Development service fee expense	17,828	0	28,832	0
Total operating expenses	119,859	119,121	236,430	248,019
Operating income	63,271	67,533	122,066	128,776
OTHER INCOME (EXPENSE)
Interest and other income	1,928	4,992	3,804	9,590
Interest expense	(21,942)	(30,131)	(44,285)	(61,543)
Total other income (expense)	(20,014)	(25,139)	(40,481)	(51,953)
Income before gain on property dispositions, income taxes and equity in earnings of unconsolidated joint ventures	43,257	42,394	81,585	76,823
Gain on property dispositions	5,895	3,832	6,702	24,353
Income taxes	(324)	(752)	(946)	(1,553)
Equity in earnings of unconsolidated joint ventures	3,990	5,583	9,721	10,497
Net income	52,818	51,057	97,062	110,120
Noncontrolling interest - consolidated joint ventures	(57)	(113)	(120)	(113)
Preferred unit distributions	(118)	(118)	(236)	(236)
Net income available to common shareholders	52,643	50,826	96,706	109,771
Comprehensive income attributable to common shareholders
Net income	52,818	51,057	97,062	110,120
Other comprehensive income (loss) - foreign currency translation	7,503	(13,509)	10,680	(18,596)
Other comprehensive (loss) income - derivative instruments	(38)	(435)	275	(1,795)
Other comprehensive income (loss)	7,465	(13,944)	10,955	(20,391)
Total comprehensive income	$ 60,283	$ 37,113	$ 108,017	$ 89,729
Weighted average number of common shares outstanding
Basic	150,216	149,534	150,130	149,541
Diluted	151,036	150,274	150,883	150,161
Net income allocated to general partners	$ 51,411	$ 49,627	$ 94,443	$ 107,181
Net income allocated to limited partners	1,350	1,317	2,499	2,826
Amounts attributable to common shareholders
Income from continuing operations	52,761	50,944	96,942	110,007
Net income available to common shareholders	$ 52,643	$ 50,826	$ 96,706	$ 109,771
Common shares [Member]
Basic:
Income per common share - basic	$ 0.35	$ 0.34	$ 0.64	$ 0.73
Diluted:
Income per common share - diluted	0.35	0.34	0.64	0.73
Distributions per common share or unit	0.40	0.475	0.80	0.95
Common Units [Member] | Liberty Property Limited Partnership [Member]
Basic:
Income per common share - basic	0.35	0.34	0.64	0.73
Diluted:
Income per common share - diluted	0.35	0.34	0.64	0.73
Distributions per common share or unit	$ 0.40	$ 0.475	$ 0.80	$ 0.95