Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net income	$ 164,615,000	$ 97,062,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	88,459,000	92,310,000
Amortization of deferred financing costs	1,922,000	1,874,000
Expensed pursuit costs	383,000	185,000
Impairment charges - real estate assets	26,000,000	0
Equity in earnings of unconsolidated joint ventures	(14,192,000)	(9,721,000)
Gain on property dispositions	(142,514,000)	(6,702,000)
Share-based compensation/Non-cash compensation	11,261,000	10,500,000
Other	(2,069,000)	(1,712,000)
Changes in operating assets and liabilities:
Accounts receivable	2,446,000	630,000
Deferred rent receivable	(10,289,000)	(10,851,000)
Prepaid expenses and other assets	27,199,000	10,274,000
Accounts payable	(5,341,000)	(4,154,000)
Accrued interest	285,000	(160,000)
Other liabilities	(11,798,000)	3,399,000
Other liabilities - development service fee	62,256,000	0
Net cash provided by operating activities	198,623,000	182,934,000
INVESTING ACTIVITIES
Investment in properties - acquisitions	(211,335,000)	(19,838,000)
Investment in properties - other	(22,104,000)	(25,562,000)
Investments in and advances to unconsolidated joint ventures	(73,922,000)	(25,333,000)
Distributions from unconsolidated joint ventures	16,522,000	12,178,000
Net proceeds from disposition of properties/land	313,055,000	26,220,000
Investment in development in progress	(96,196,000)	(136,030,000)
Investment in land held for development	(105,827,000)	(87,255,000)
Payment of deferred leasing costs	(13,399,000)	(18,750,000)
Release of escrows and other	126,203,000	26,315,000
Net cash used in investing activities	(67,003,000)	(248,055,000)
FINANCING ACTIVITIES
Net proceeds from issuance of common shares	4,527,000	4,223,000
Share repurchase including shares related to tax withholdings	(4,500,000)	(4,668,000)
Repayments of mortgage loans	(30,377,000)	(3,876,000)
Proceeds from credit facility	698,163,000	284,000,000
Repayments on credit facility	(662,879,000)	(107,000,000)
Distribution paid on common shares	(118,089,000)	(128,703,000)
Distributions to partners/noncontrolling interests	(3,296,000)	(3,569,000)
Net cash (used in) provided by financing activities	(116,451,000)	40,407,000
Net increase (decrease) in cash, cash equivalents and restricted cash	15,169,000	(24,714,000)
(Decrease) increase in cash, cash equivalents and restricted cash related to foreign currency translation	(1,778,000)	1,552,000
Cash, cash equivalents and restricted cash at beginning of period	25,685,000	56,025,000
Cash, cash equivalents and restricted cash at end of period	39,076,000	32,863,000
Liberty Property Limited Partnership [Member]
OPERATING ACTIVITIES
Net income	164,615,000	97,062,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	88,459,000	92,310,000
Amortization of deferred financing costs	1,922,000	1,874,000
Expensed pursuit costs	383,000	185,000
Impairment charges - real estate assets	26,000,000	0
Equity in earnings of unconsolidated joint ventures	(14,192,000)	(9,721,000)
Gain on property dispositions	(142,514,000)	(6,702,000)
Share-based compensation/Non-cash compensation	11,261,000	10,500,000
Other	(2,069,000)	(1,712,000)
Changes in operating assets and liabilities:
Accounts receivable	2,446,000	630,000
Deferred rent receivable	(10,289,000)	(10,851,000)
Prepaid expenses and other assets	27,199,000	10,274,000
Accounts payable	(5,341,000)	(4,154,000)
Accrued interest	285,000	(160,000)
Other liabilities	(11,798,000)	3,399,000
Other liabilities - development service fee	62,256,000	0
Net cash provided by operating activities	198,623,000	182,934,000
INVESTING ACTIVITIES
Investment in properties - acquisitions	(211,335,000)	(19,838,000)
Investment in properties - other	(22,104,000)	(25,562,000)
Investments in and advances to unconsolidated joint ventures	(73,922,000)	(25,333,000)
Distributions from unconsolidated joint ventures	16,522,000	12,178,000
Net proceeds from disposition of properties/land	313,055,000	26,220,000
Investment in development in progress	(96,196,000)	(136,030,000)
Investment in land held for development	(105,827,000)	(87,255,000)
Payment of deferred leasing costs	(13,399,000)	(18,750,000)
Release of escrows and other	126,203,000	26,315,000
Net cash used in investing activities	(67,003,000)	(248,055,000)
FINANCING ACTIVITIES
Repayments of mortgage loans	(30,377,000)	(3,876,000)
Proceeds from credit facility	698,163,000	284,000,000
Repayments on credit facility	(662,879,000)	(107,000,000)
Capital contributions	4,527,000	4,223,000
Distributions to partners/noncontrolling interests	(125,885,000)	(136,940,000)
Net cash (used in) provided by financing activities	(116,451,000)	40,407,000
Net increase (decrease) in cash, cash equivalents and restricted cash	15,169,000	(24,714,000)
(Decrease) increase in cash, cash equivalents and restricted cash related to foreign currency translation	(1,778,000)	1,552,000
Cash, cash equivalents and restricted cash at beginning of period	25,685,000	56,025,000
Cash, cash equivalents and restricted cash at end of period	$ 39,076,000	$ 32,863,000