Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net income	$ 366,145	$ 245,924	$ 224,471
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	207,673	229,779	236,075
Amortization of deferred financing costs	3,974	4,395	4,811
Impairment - real estate assets	3,879	18,244	117
Loss on debt extinguishment	27,099	0	0
Equity in earnings of unconsolidated joint ventures	(21,970)	(3,149)	(10,314)
Distributions from unconsolidated joint ventures	0	2,444	0
Gain on property dispositions	(219,270)	(100,314)	(91,778)
Share-based compensation	14,478	12,919	12,457
Other	(6,128)	(9,937)	(7,935)
Changes in operating assets and liabilities:
Restricted cash	4,352	10,478	30,286
Accounts receivable	421	1,009	(1,770)
Deferred rent receivable	(16,927)	(23,167)	(15,263)
Prepaid expenses and other assets	(16,766)	(14,540)	(28,360)
Accounts payable	8,943	1,822	5,299
Accrued interest	(4,276)	1,641	(1,264)
Other liabilities	(18,606)	7,818	(20,348)
Net cash provided by operating activities	333,021	385,366	336,484
INVESTING ACTIVITIES
Investment in properties – acquisitions	(9,216)	(111,811)	(124,962)
Investment in properties – other	(54,249)	(77,626)	(102,466)
Investments in and advances to unconsolidated joint ventures	(70,581)	(43,676)	(22,243)
Distributions from unconsolidated joint ventures	63,048	33,195	15,330
Net proceeds from disposition of properties/land	1,192,918	530,440	559,322
Investment in development in progress	(342,489)	(210,677)	(288,375)
Investment in land held for development	(110,082)	(150,523)	(105,324)
Payment of deferred leasing costs	(32,682)	(48,672)	(40,123)
Other	(23,265)	(10,310)	2,504
Net cash provided by (used in) investing activities	613,402	(89,660)	(106,337)
FINANCING ACTIVITIES
Net proceeds from issuance of common shares	13,029	38,797	58,473
Share repurchase	(40,896)	(71,802)	0
Proceeds from unsecured notes	396,648	398,576	0
Repayments of unsecured notes including prepayment premium	(723,368)	(316,000)	(200,000)
Repayments of mortgage loans	(29,538)	(175,364)	(56,156)
Proceeds from credit facility	591,300	1,122,700	517,550
Repayments on credit facility	(850,300)	(1,030,700)	(350,550)
Payment of deferred financing costs	(3,550)	(3,656)	(3,629)
Distribution paid on common shares	(279,248)	(282,582)	(280,136)
Distribution paid on units/noncontrolling interests	(8,212)	(7,596)	(7,453)
Net cash used in financing activities	(934,135)	(327,627)	(321,901)
Net (decrease) increase in cash and cash equivalents	12,288	(31,921)	(91,754)
Decrease in cash and cash equivalents related to foreign currency translation	(3,999)	(2,072)	(2,314)
Cash and cash equivalents at beginning of year	35,353	69,346	163,414
Cash and cash equivalents at end of year	43,642	35,353	69,346
Liberty Property Limited Partnership [Member]
OPERATING ACTIVITIES
Net income	366,145	245,924	224,471
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	207,673	229,779	236,075
Amortization of deferred financing costs	3,974	4,395	4,811
Impairment - real estate assets	3,879	18,244	117
Loss on debt extinguishment	27,099	0	0
Equity in earnings of unconsolidated joint ventures	(21,970)	(3,149)	(10,314)
Distributions from unconsolidated joint ventures	0	2,444	0
Gain on property dispositions	(219,270)	(100,314)	(91,778)
Share-based compensation	14,478	12,919	12,457
Other	(6,128)	(9,937)	(7,935)
Changes in operating assets and liabilities:
Restricted cash	4,352	10,478	30,286
Accounts receivable	421	1,009	(1,770)
Deferred rent receivable	(16,927)	(23,167)	(15,263)
Prepaid expenses and other assets	(16,766)	(14,540)	(28,360)
Accounts payable	8,943	1,822	5,299
Accrued interest	(4,276)	1,641	(1,264)
Other liabilities	(18,606)	7,818	(20,348)
Net cash provided by operating activities	333,021	385,366	336,484
INVESTING ACTIVITIES
Investment in properties – acquisitions	(9,216)	(111,811)	(124,962)
Investment in properties – other	(54,249)	(77,626)	(102,466)
Investments in and advances to unconsolidated joint ventures	(70,581)	(43,676)	(22,243)
Distributions from unconsolidated joint ventures	63,048	33,195	15,330
Net proceeds from disposition of properties/land	1,192,918	530,440	559,322
Investment in development in progress	(342,489)	(210,677)	(288,375)
Investment in land held for development	(110,082)	(150,523)	(105,324)
Payment of deferred leasing costs	(32,682)	(48,672)	(40,123)
Other	(23,265)	(10,310)	2,504
Net cash provided by (used in) investing activities	613,402	(89,660)	(106,337)
FINANCING ACTIVITIES
Proceeds from unsecured notes	396,648	398,576	0
Repayments of unsecured notes including prepayment premium	(723,368)	(316,000)	(200,000)
Repayments of mortgage loans	(29,538)	(175,364)	(56,156)
Proceeds from credit facility	591,300	1,122,700	517,550
Repayments on credit facility	(850,300)	(1,030,700)	(350,550)
Payment of deferred financing costs	(3,550)	(3,656)	(3,629)
Capital contributions	13,029	38,797	58,473
Distributions to partners/noncontrolling interest holders	(328,356)	(361,980)	(287,589)
Net cash used in financing activities	(934,135)	(327,627)	(321,901)
Net (decrease) increase in cash and cash equivalents	12,288	(31,921)	(91,754)
Decrease in cash and cash equivalents related to foreign currency translation	(3,999)	(2,072)	(2,314)
Cash and cash equivalents at beginning of year	35,353	69,346	163,414
Cash and cash equivalents at end of year	$ 43,642	$ 35,353	$ 69,346