Summary of Significant Accounting Policies (Adjustment of Previously Reported Financial Information, Cash Flow) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ 200,291	$ 55,734	$ 51,057	$ 59,063	$ 83,841	$ 93,695	$ 36,526	$ 31,862	$ 366,145	$ 245,924	$ 224,471
Other liabilities									(18,606)	7,818	(20,348)
Liberty Property Limited Partnership [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income									366,145	245,924	224,471
Other liabilities									(18,606)	7,818	(20,348)
Restatement of Net Profit (Loss) [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income										245,924	224,471
Other liabilities										7,818	(20,348)
Restatement of Net Profit (Loss) [Member] | Liberty Property Limited Partnership [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income										245,924	224,471
Other liabilities										7,818	(20,348)
Previously Reported [Member] | Restatement of Net Profit (Loss) [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income										244,446	224,163
Other liabilities										9,296	(20,040)
Previously Reported [Member] | Restatement of Net Profit (Loss) [Member] | Liberty Property Limited Partnership [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income										244,446	224,163
Other liabilities										9,296	(20,040)
Adjustment [Member] | Restatement of Net Profit (Loss) [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income									$ (500)	1,478	308
Other liabilities										(1,478)	(308)
Adjustment [Member] | Restatement of Net Profit (Loss) [Member] | Liberty Property Limited Partnership [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income										1,478	308
Other liabilities										$ (1,478)	$ (308)