Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
OPERATING REVENUE
Rental	$ 143,294	$ 110,260	$ 421,620	$ 321,932
Operating expense reimbursement	55,062	45,088	167,326	131,566
Total operating revenue	198,356	155,348	588,946	453,498
OPERATING EXPENSE
Rental property	33,105	27,634	103,728	79,547
Real estate taxes	25,595	18,925	75,812	55,788
General and administrative	14,748	17,217	48,077	53,466
Depreciation and amortization	58,578	39,159	173,184	113,906
Total operating expenses	132,026	102,935	400,801	302,707
Operating income	66,330	52,413	188,145	150,791
OTHER INCOME (EXPENSE)
Other income	6,230	4,512	11,785	14,269
Interest expense	(37,958)	(33,542)	(115,635)	(89,414)
Total other income (expense)	(31,728)	(29,030)	(103,850)	(75,145)
Income before (loss) gain on property dispositions, income taxes and equity in earnings of unconsolidated joint ventures	34,602	23,383	84,295	75,646
(Loss) gain on property dispositions	(20)	0	1,879	0
Income taxes	(859)	(629)	(2,083)	(1,780)
Equity in earnings of unconsolidated joint ventures	1,592	650	7,297	3,973
Income from continuing operations	35,315	23,404	91,388	77,839
Discontinued operations (including net gain on property dispositions of $38 and $29 for the quarters ended September 30, 2014 and 2013, respectively and $46,291 and $49,367 for the nine month periods ended September 30, 2014 and 2013, respectively)	136	6,544	48,276	70,008
Net income	35,451	29,948	139,664	147,847
Noncontrolling interest – operating partnership	(944)	(843)	(3,618)	(7,394)
Noncontrolling interest - consolidated joint ventures	(84)	(406)	(474)	(406)
Net income available to common shareholders	34,423	28,699	135,572	140,047
Comprehensive income attributable to common shareholders
Net income	35,451	29,948	139,664	147,847
Other comprehensive (loss) income - foreign currency translation	(13,000)	4,927	(5,189)	115
Other comprehensive income (loss) - change in net unrealized gain on derivative instruments	666	0	(990)	0
Other comprehensive (loss) income	(12,334)	4,927	(6,179)	115
Total comprehensive income	23,117	34,875	133,485	147,962
Less: comprehensive income attributable to noncontrolling interest	(739)	(1,370)	(3,948)	(7,777)
Comprehensive income attributable to common shareholders	22,378	33,505	129,537	140,185
Weighted average number of common shares outstanding
Basic	147,422	135,628	146,987	124,889
Diluted	148,088	136,328	147,661	125,655
Amounts attributable to common shareholders
Income from continuing operations	34,290	22,316	88,430	72,048
Discontinued operations	133	6,383	47,142	67,999
Net income available to common shareholders	34,423	28,699	135,572	140,047
Liberty Property Limited Partnership [Member]
OPERATING REVENUE
Rental	143,294	110,260	421,620	321,932
Operating expense reimbursement	55,062	45,088	167,326	131,566
Total operating revenue	198,356	155,348	588,946	453,498
OPERATING EXPENSE
Rental property	33,105	27,634	103,728	79,547
Real estate taxes	25,595	18,925	75,812	55,788
General and administrative	14,748	17,217	48,077	53,466
Depreciation and amortization	58,578	39,159	173,184	113,906
Total operating expenses	132,026	102,935	400,801	302,707
Operating income	66,330	52,413	188,145	150,791
OTHER INCOME (EXPENSE)
Other income	6,230	4,512	11,785	14,269
Interest expense	(37,958)	(33,542)	(115,635)	(89,414)
Total other income (expense)	(31,728)	(29,030)	(103,850)	(75,145)
Income before (loss) gain on property dispositions, income taxes and equity in earnings of unconsolidated joint ventures	34,602	23,383	84,295	75,646
(Loss) gain on property dispositions	(20)	0	1,879	0
Income taxes	(859)	(629)	(2,083)	(1,780)
Equity in earnings of unconsolidated joint ventures	1,592	650	7,297	3,973
Income from continuing operations	35,315	23,404	91,388	77,839
Discontinued operations (including net gain on property dispositions of $38 and $29 for the quarters ended September 30, 2014 and 2013, respectively and $46,291 and $49,367 for the nine month periods ended September 30, 2014 and 2013, respectively)	136	6,544	48,276	70,008
Net income	35,451	29,948	139,664	147,847
Noncontrolling interest - consolidated joint ventures	(84)	(406)	(474)	(406)
Preferred unit distributions	(118)	(118)	(354)	(2,001)
Excess of preferred unit redemption over carrying amount			0	(1,236)
Net income available to common shareholders	35,249	29,424	138,836	144,204
Comprehensive income attributable to common shareholders
Net income	35,451	29,948	139,664	147,847
Other comprehensive (loss) income - foreign currency translation	(13,000)	4,927	(5,189)	115
Other comprehensive income (loss) - change in net unrealized gain on derivative instruments	666	0	(990)	0
Other comprehensive (loss) income	(12,334)	4,927	(6,179)	115
Total comprehensive income	23,117	34,875	133,485	147,962
Weighted average number of common shares outstanding
Basic	150,976	139,320	150,541	128,595
Diluted	151,642	140,020	151,215	129,361
Net income allocated to general partners	34,423	28,699	135,572	140,047
Net income allocated to limited partners	944	843	3,618	7,394
Amounts attributable to common shareholders
Income from continuing operations	35,231	22,998	90,914	77,433
Net income available to common shareholders	$ 35,249	$ 29,424	$ 138,836	$ 144,204
Common shares [Member]
Basic:
Income from continuing operations	$ 0.23	$ 0.16	$ 0.60	$ 0.58
Income from discontinued operations	$ 0.00	$ 0.05	$ 0.32	$ 0.54
Income per common share - basic	$ 0.23	$ 0.21	$ 0.92	$ 1.12
Diluted:
Income from continuing operations	$ 0.23	$ 0.16	$ 0.60	$ 0.57
Income from discontinued operations	$ 0.00	$ 0.05	$ 0.32	$ 0.54
Income per common share - diluted	$ 0.23	$ 0.21	$ 0.92	$ 1.11
Distributions per common share or unit	$ 0.475	$ 0.475	$ 1.425	$ 1.425
Common Units [Member] | Liberty Property Limited Partnership [Member]
Basic:
Income from continuing operations	$ 0.23	$ 0.16	$ 0.60	$ 0.58
Income from discontinued operations	$ 0.00	$ 0.05	$ 0.32	$ 0.54
Income per common share - basic	$ 0.23	$ 0.21	$ 0.92	$ 1.12
Diluted:
Income from continuing operations	$ 0.23	$ 0.16	$ 0.60	$ 0.57
Income from discontinued operations	$ 0.00	$ 0.05	$ 0.32	$ 0.54
Income per common share - diluted	$ 0.23	$ 0.21	$ 0.92	$ 1.11
Distributions per common share or unit	$ 0.475	$ 0.475	$ 1.425	$ 1.425