Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
OPERATING REVENUE
Rental	$ 147,367	$ 139,377	$ 295,952	$ 278,326
Operating expense reimbursement	56,151	53,583	114,467	112,264
Total operating revenue	203,518	192,960	410,419	390,590
OPERATING EXPENSE
Rental property	31,949	31,982	67,520	70,623
Real estate taxes	26,462	25,716	52,626	50,217
General and administrative	17,053	14,973	35,855	33,329
Depreciation and amortization	56,833	57,872	115,629	114,606
Impairment - real estate assets	1,036	0	16,775	0
Total operating expenses	133,333	130,543	288,405	268,775
Operating income	70,185	62,417	122,014	121,815
OTHER INCOME (EXPENSE)
Other income	6,581	3,115	12,952	5,553
Interest expense	(35,066)	(38,470)	(69,736)	(77,677)
Total other income (expense)	(28,485)	(35,355)	(56,784)	(72,124)
Income before gain on property dispositions, income taxes and equity in (loss) earnings of unconsolidated joint ventures	41,700	27,062	65,230	49,691
Gain on property dispositions	1,249	1,897	3,520	1,898
Income taxes	(1,169)	(693)	(2,014)	(1,224)
Equity in (loss) earnings of unconsolidated joint ventures	(5,254)	1,546	1,652	5,705
Income from continuing operations	36,526	29,812	68,388	56,070
Discontinued operations (including net gain on property dispositions of $139 for the three months ended June 30, 2014 and $46,254 for the six months ended June 30, 2014)	0	295	0	48,143
Net income	36,526	30,107	68,388	104,213
Noncontrolling interest – operating partnership	(958)	(821)	(1,811)	(2,674)
Noncontrolling interest - consolidated joint ventures	(55)	(37)	(113)	(390)
Net income available to common shareholders	35,513	29,249	66,464	101,149
Comprehensive income attributable to common shareholders
Net income	36,526	30,107	68,388	104,213
Other comprehensive income - foreign currency translation	12,151	6,464	1,741	7,811
Other comprehensive income (loss) - derivative instruments	628	(1,145)	(319)	(1,656)
Other comprehensive income	12,779	5,319	1,422	6,155
Total comprehensive income	49,305	35,426	69,810	110,368
Less: comprehensive income attributable to noncontrolling interest	(1,309)	(983)	(1,957)	(3,209)
Comprehensive income attributable to common shareholders	$ 47,996	$ 34,443	$ 67,853	$ 107,159
Weighted average number of common shares outstanding
Basic	148,778	147,012	148,574	146,749
Diluted	149,454	147,774	149,247	147,444
Amounts attributable to common shareholders
Income from continuing operations	$ 35,513	$ 28,961	$ 66,464	$ 54,137
Discontinued operations	0	288	0	47,012
Net income available to common shareholders	35,513	29,249	66,464	101,149
Liberty Property Limited Partnership [Member]
OPERATING REVENUE
Rental	147,367	139,377	295,952	278,326
Operating expense reimbursement	56,151	53,583	114,467	112,264
Total operating revenue	203,518	192,960	410,419	390,590
OPERATING EXPENSE
Rental property	31,949	31,982	67,520	70,623
Real estate taxes	26,462	25,716	52,626	50,217
General and administrative	17,053	14,973	35,855	33,329
Depreciation and amortization	56,833	57,872	115,629	114,606
Impairment - real estate assets	1,036	0	16,775	0
Total operating expenses	133,333	130,543	288,405	268,775
Operating income	70,185	62,417	122,014	121,815
OTHER INCOME (EXPENSE)
Other income	6,581	3,115	12,952	5,553
Interest expense	(35,066)	(38,470)	(69,736)	(77,677)
Total other income (expense)	(28,485)	(35,355)	(56,784)	(72,124)
Income before gain on property dispositions, income taxes and equity in (loss) earnings of unconsolidated joint ventures	41,700	27,062	65,230	49,691
Gain on property dispositions	1,249	1,897	3,520	1,898
Income taxes	(1,169)	(693)	(2,014)	(1,224)
Equity in (loss) earnings of unconsolidated joint ventures	(5,254)	1,546	1,652	5,705
Income from continuing operations	36,526	29,812	68,388	56,070
Discontinued operations (including net gain on property dispositions of $139 for the three months ended June 30, 2014 and $46,254 for the six months ended June 30, 2014)	0	295	0	48,143
Net income	36,526	30,107	68,388	104,213
Noncontrolling interest - consolidated joint ventures	(55)	(37)	(113)	(390)
Preferred unit distributions	(118)	(118)	(236)	(236)
Net income available to common shareholders	36,353	29,952	68,039	103,587
Comprehensive income attributable to common shareholders
Net income	36,526	30,107	68,388	104,213
Other comprehensive income - foreign currency translation	12,151	6,464	1,741	7,811
Other comprehensive income (loss) - derivative instruments	628	(1,145)	(319)	(1,656)
Other comprehensive income	12,779	5,319	1,422	6,155
Total comprehensive income	$ 49,305	$ 35,426	$ 69,810	$ 110,368
Weighted average number of common shares outstanding
Basic	152,317	150,563	152,114	150,304
Diluted	152,993	151,325	152,787	150,999
Net income allocated to general partners	$ 35,513	$ 29,249	$ 66,464	$ 101,149
Net income allocated to limited partners	958	821	1,811	2,674
Amounts attributable to common shareholders
Income from continuing operations	36,471	29,775	68,275	55,680
Net income available to common shareholders	$ 36,353	$ 29,952	$ 68,039	$ 103,587
Common shares [Member]
Basic:
Income from continuing operations	$ 0.24	$ 0.20	$ 0.45	$ 0.37
Income from discontinued operations	0.00	0.00	0.00	0.32
Income per common share - basic	0.24	0.20	0.45	0.69
Diluted:
Income from continuing operations	0.24	0.20	0.45	0.37
Income from discontinued operations	0.00	0.00	0.00	0.32
Income per common share - diluted	0.24	0.20	0.45	0.69
Distributions per common share or unit	0.475	0.475	0.95	0.95
Common Units [Member] | Liberty Property Limited Partnership [Member]
Basic:
Income from continuing operations	0.24	0.20	0.45	0.37
Income from discontinued operations	0.00	0.00	0.00	0.32
Income per common share - basic	0.24	0.20	0.45	0.69
Diluted:
Income from continuing operations	0.24	0.20	0.45	0.37
Income from discontinued operations	0.00	0.00	0.00	0.32
Income per common share - diluted	0.24	0.20	0.45	0.69
Distributions per common share or unit	$ 0.475	$ 0.475	$ 0.95	$ 0.95