Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES
Net income	$ 244,446	$ 224,163	$ 219,594
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	229,779	236,075	205,147
Amortization of deferred financing costs	4,395	4,811	4,084
Impairment - real estate assets	18,244	117	248
Equity in earnings of unconsolidated joint ventures	(3,149)	(10,314)	(6,067)
Distributions from unconsolidated joint ventures	2,444	0	844
Gain on property dispositions	(100,314)	(91,778)	(98,651)
Share-based and Noncash compensation	12,919	12,457	9,976
Other	(9,937)	(7,935)	(8,311)
Changes in operating assets and liabilities:
Restricted cash	10,478	30,286	(18,397)
Accounts receivable	1,009	(1,770)	(4,889)
Deferred rent receivable	(23,167)	(15,263)	(9,473)
Prepaid expenses and other assets	(14,540)	(28,360)	(22,424)
Accounts payable	1,822	5,299	15,703
Accrued interest	1,641	(1,264)	5,613
Other liabilities	9,296	(20,040)	22,968
Net cash provided by operating activities	385,366	336,484	315,965
INVESTING ACTIVITIES
Investment in properties - acquisitions	(111,811)	(124,962)	(1,429,822)
Investment in properties - other	(77,626)	(102,466)	(74,345)
Investments in and advances to unconsolidated joint ventures	(43,676)	(22,243)	(16,185)
Distributions from unconsolidated joint ventures	33,195	15,330	13,774
Net proceeds from disposition of properties/land	530,440	559,322	526,949
Investment in development in progress	(210,677)	(288,375)	(123,879)
Investment in land held for development	(150,523)	(105,324)	(67,326)
Investment in deferred leasing costs	(48,672)	(40,123)	(36,901)
Other investing activities	(10,310)	2,504	9,821
Net cash used in investing activities	(89,660)	(106,337)	(1,197,914)
FINANCING ACTIVITIES
Net proceeds from issuance of Common Shares	38,797	58,473	969,468
Share repurchase	(71,802)	0	0
Redemption of preferred units	0	0	(64,500)
Proceeds from unsecured notes	398,576	0	448,646
Repayments of unsecured notes	(316,000)	(200,000)	0
Proceeds from mortgage loans	0	0	10,401
Repayments of mortgage loans	(175,364)	(56,156)	(10,605)
Proceeds from credit facility	1,122,700	517,550	611,550
Repayments on credit facility	(1,030,700)	(350,550)	(703,550)
Payment of deferred financing costs	(3,656)	(3,629)	(5,866)
Distribution paid on Common Shares	(282,582)	(280,136)	(240,340)
Distribution paid on units	(7,596)	(7,453)	(9,438)
Net cash (used in) provided by financing activities	(327,627)	(321,901)	1,005,766
Net (decrease) increase in cash and cash equivalents	(31,921)	(91,754)	123,817
(Decrease) increase in cash and cash equivalents related to foreign currency translation	(2,072)	(2,314)	1,241
Cash and cash equivalents at beginning of year	69,346	163,414	38,356
Cash and cash equivalents at end of year	35,353	69,346	163,414
Liberty Property Limited Partnership [Member]
OPERATING ACTIVITIES
Net income	244,446	224,163	219,594
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	229,779	236,075	205,147
Amortization of deferred financing costs	4,395	4,811	4,084
Impairment - real estate assets	18,244	117	248
Equity in earnings of unconsolidated joint ventures	(3,149)	(10,314)	(6,067)
Distributions from unconsolidated joint ventures	2,444	0	844
Gain on property dispositions	(100,314)	(91,778)	(98,651)
Share-based and Noncash compensation	12,919	12,457	9,976
Other	(9,937)	(7,935)	(8,311)
Changes in operating assets and liabilities:
Restricted cash	10,478	30,286	(18,397)
Accounts receivable	1,009	(1,770)	(4,889)
Deferred rent receivable	(23,167)	(15,263)	(9,473)
Prepaid expenses and other assets	(14,540)	(28,360)	(22,424)
Accounts payable	1,822	5,299	15,703
Accrued interest	1,641	(1,264)	5,613
Other liabilities	9,296	(20,040)	22,968
Net cash provided by operating activities	385,366	336,484	315,965
INVESTING ACTIVITIES
Investment in properties - acquisitions	(111,811)	(124,962)	(1,429,822)
Investment in properties - other	(77,626)	(102,466)	(74,345)
Investments in and advances to unconsolidated joint ventures	(43,676)	(22,243)	(16,185)
Distributions from unconsolidated joint ventures	33,195	15,330	13,774
Net proceeds from disposition of properties/land	530,440	559,322	526,949
Investment in development in progress	(210,677)	(288,375)	(123,879)
Investment in land held for development	(150,523)	(105,324)	(67,326)
Investment in deferred leasing costs	(48,672)	(40,123)	(36,901)
Other investing activities	(10,310)	2,504	9,821
Net cash used in investing activities	(89,660)	(106,337)	(1,197,914)
FINANCING ACTIVITIES
Redemption of preferred units	0	0	(64,500)
Proceeds from unsecured notes	398,576	0	448,646
Repayments of unsecured notes	(316,000)	(200,000)	0
Proceeds from mortgage loans	0	0	10,401
Repayments of mortgage loans	(175,364)	(56,156)	(10,605)
Proceeds from credit facility	1,122,700	517,550	611,550
Repayments on credit facility	(1,030,700)	(350,550)	(703,550)
Payment of deferred financing costs	(3,656)	(3,629)	(5,866)
Capital contributions	38,797	58,473	969,468
Distributions to partners	(361,980)	(287,589)	(249,778)
Net cash (used in) provided by financing activities	(327,627)	(321,901)	1,005,766
Net (decrease) increase in cash and cash equivalents	(31,921)	(91,754)	123,817
(Decrease) increase in cash and cash equivalents related to foreign currency translation	(2,072)	(2,314)	1,241
Cash and cash equivalents at beginning of year	69,346	163,414	38,356
Cash and cash equivalents at end of year	$ 35,353	$ 69,346	$ 163,414