Shareholders' Equity - Trust (Common Shares) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Aug. 31, 2015 USD ($)
Common Units
Units issued in connection with acquisitions | shares	0	0	0
Continuous Equity Offering
Maximum equity capacity	$ 200,000,000
Equity available	$ 125,000,000
Shares issued during period under continuous equity offerings, shares, new issues | shares	0	0	0
Share Repurchase
Share repurchase, value	$ 40,896,000	$ 71,802,000
Common units [Member]
Common Shares
Common units distributions (USD per share)	$ 285,900,000	$ 289,300,000	$ 286,900,000
Ordinary dividend (USD per share) | $ / shares	$ 1.0319	$ 1.4348	$ 1.2556
Qualified dividend (USD per share) | $ / shares	0.0013	0	0
Capital gain - 20% (USD per share) | $ / shares	0	0.1112	0
IRC Sec 1250 unrecapture gain - 25% (USD per share) | $ / shares	0.6176	0.3372	0.3712
Return of capital (USD per share) | $ / shares	0.2492	0.0168	0.2732
Total (USD per share) | $ / shares	$ 1.9	$ 1.9000	$ 1.9000
Common shares [Member]
Dividend Reinvestment and Share Purchase Plan
Dividend reinvestment plan | shares	56,426	1,036,437	1,643,536
Share Repurchase
Share repurchase, shares | shares	1,396,844	2,321,794
2015 Share Repurchase Program [Member] | Common shares [Member]
Share Repurchase
Stock repurchase program, authorized amount				$ 250,000,000
Share repurchase, shares | shares	1,400,000	2,300,000
Share repurchase, value	$ 40,900,000	$ 71,800,000
Liberty Property Limited Partnership [Member]
Common Units
Common units outstanding | shares	3,530,031	3,539,075
Closing price of the common shares	$ 139,400,000
Units issued in connection with acquisitions | shares	0	0	0
Share Repurchase
Share repurchase, value	$ 40,896,000	$ 71,802,000
Liberty Property Limited Partnership [Member] | Common units [Member]
Dividend Reinvestment and Share Purchase Plan
Dividend reinvestment plan | shares	56,426	1,036,437	1,643,536
Liberty Property Limited Partnership [Member] | 2015 Share Repurchase Program [Member] | Common units [Member]
Share Repurchase
Stock repurchase program, authorized amount				$ 250,000,000
Share repurchase, shares | shares	1,400,000	2,300,000
Share repurchase, value	$ 40,900,000	$ 71,800,000
Conversion Ratio of Common Units to Common Shares [Member]
Common Units
Common unit, convertible to common stock	1
Common stock, converted from common unit	1