Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
OPERATING ACTIVITIES
Net income	$ 162,085,000	$ 139,664,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	173,726,000	176,207,000
Amortization of deferred financing costs	3,249,000	3,727,000
Impairment - real estate assets	16,775,000	0
Equity in earnings of unconsolidated joint ventures	(805,000)	(7,297,000)
Distributions from unconsolidated joint ventures	2,490,000	0
Gain on property dispositions	(56,987,000)	(48,170,000)
Share-based compensation/Non-cash compensation	10,709,000	10,422,000
Other	(8,143,000)	(5,202,000)
Changes in operating assets and liabilities:
Restricted cash	4,914,000	28,469,000
Accounts receivable	1,023,000	(4,771,000)
Deferred rent receivable	(17,122,000)	(11,928,000)
Prepaid expenses and other assets	(20,182,000)	(38,882,000)
Accounts payable	8,312,000	18,824,000
Accrued interest	19,258,000	15,500,000
Other liabilities	371,000	(26,232,000)
Net cash provided by operating activities	299,673,000	250,331,000
INVESTING ACTIVITIES
Investment in operating properties - acquisitions	(100,756,000)	(97,677,000)
Investment in operating properties - other	(58,038,000)	(61,480,000)
Investments in and advances to unconsolidated joint ventures	(30,609,000)	(13,894,000)
Distributions from unconsolidated joint ventures	23,093,000	10,213,000
Net proceeds from disposition of properties/land	243,943,000	351,301,000
Investment in development in progress	(123,547,000)	(222,484,000)
Investment in land held for development	(101,934,000)	(73,547,000)
Investment in deferred leasing costs	(34,404,000)	(28,409,000)
Other	(6,366,000)	5,501,000
Net cash used in investing activities	(188,618,000)	(130,476,000)
FINANCING ACTIVITIES
Net proceeds from issuance of common shares	38,195,000	44,097,000
Payments for Repurchase of Common Stock	(65,463,000)	0
Proceeds from unsecured notes	398,576,000	0
Repayment of unsecured notes	(300,000,000)	(200,000,000)
Repayments of mortgage loans	(112,970,000)	(9,329,000)
Proceeds from credit facility	919,700,000	179,750,000
Repayments on credit facility	(786,700,000)	(38,800,000)
Payment of deferred financing costs	(3,478,000)	(3,622,000)
Distribution paid on common shares	(212,402,000)	(209,779,000)
Distribution paid on units	(5,704,000)	(5,692,000)
Net cash used in financing activities	(130,246,000)	(243,375,000)
Net decrease in cash and cash equivalents	(19,191,000)	(123,520,000)
Decrease in cash and cash equivalents related to foreign currency translation	(1,503,000)	(808,000)
Cash and cash equivalents at beginning of period	69,346,000	163,414,000
Cash and cash equivalents at end of period	48,652,000	39,086,000
Liberty Property Limited Partnership [Member]
OPERATING ACTIVITIES
Net income	162,085,000	139,664,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	173,726,000	176,207,000
Amortization of deferred financing costs	3,249,000	3,727,000
Impairment - real estate assets	16,775,000	0
Equity in earnings of unconsolidated joint ventures	(805,000)	(7,297,000)
Distributions from unconsolidated joint ventures	2,490,000	0
Gain on property dispositions	(56,987,000)	(48,170,000)
Share-based compensation/Non-cash compensation	10,709,000	10,422,000
Other	(8,143,000)	(5,202,000)
Changes in operating assets and liabilities:
Restricted cash	4,914,000	28,469,000
Accounts receivable	1,023,000	(4,771,000)
Deferred rent receivable	(17,122,000)	(11,928,000)
Prepaid expenses and other assets	(20,182,000)	(38,882,000)
Accounts payable	8,312,000	18,824,000
Accrued interest	19,258,000	15,500,000
Other liabilities	371,000	(26,232,000)
Net cash provided by operating activities	299,673,000	250,331,000
INVESTING ACTIVITIES
Investment in operating properties - acquisitions	(100,756,000)	(97,677,000)
Investment in operating properties - other	(58,038,000)	(61,480,000)
Investments in and advances to unconsolidated joint ventures	(30,609,000)	(13,894,000)
Distributions from unconsolidated joint ventures	23,093,000	10,213,000
Net proceeds from disposition of properties/land	243,943,000	351,301,000
Investment in development in progress	(123,547,000)	(222,484,000)
Investment in land held for development	(101,934,000)	(73,547,000)
Investment in deferred leasing costs	(34,404,000)	(28,409,000)
Other	(6,366,000)	5,501,000
Net cash used in investing activities	(188,618,000)	(130,476,000)
FINANCING ACTIVITIES
Payments for Repurchase of Common Stock	(65,463,000)	0
Proceeds from unsecured notes	398,576,000	0
Repayment of unsecured notes	(300,000,000)	(200,000,000)
Repayments of mortgage loans	(112,970,000)	(9,329,000)
Proceeds from credit facility	919,700,000	179,750,000
Repayments on credit facility	(786,700,000)	(38,800,000)
Payment of deferred financing costs	(3,478,000)	(3,622,000)
Capital contributions	38,195,000	44,097,000
Distributions to partners	(218,106,000)	(215,471,000)
Net cash used in financing activities	(130,246,000)	(243,375,000)
Net decrease in cash and cash equivalents	(19,191,000)	(123,520,000)
Decrease in cash and cash equivalents related to foreign currency translation	(1,503,000)	(808,000)
Cash and cash equivalents at beginning of period	69,346,000	163,414,000
Cash and cash equivalents at end of period	$ 48,652,000	$ 39,086,000