Marketable Securities (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Investment Holdings [Line Items]
Fair Value	$ 33,363,000	$ 31,522,000
Macerich Interest [Member]
Investment Holdings [Line Items]
Macerich Common Shares (in shares)	535,265	535,265
Economic basis per share (in dollars per share)	$ 56.05
GAAP Cost	30,000,000
Fair Value	$ 33,363,000	$ 31,522,000
Closing share price (in dollars per share)	$ 62.33	$ 58.89