Marketable Securities (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Marketable Securities
Marketable securities	$ 34,471,000	$ 37,918,000
Fair Value	$ 34,471,000	$ 37,918,000
Macerich interest
Marketable Securities
Macerich Common Shares	535,265	535,265
Economic basis per share (in dollars per share)	$ 56.05
GAAP Cost	$ 30,000,000
Fair Value	$ 34,471,000	$ 37,918,000
Closing share price (in dollars per share)	$ 64.4	$ 70.84