Marketable Securities (Details) (Macerich Interest [Member], USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2013
Macerich Interest [Member]
Schedule Of Available For Sale Securities [Line Items]
Macerich common shares	535,265	535,265
Economic basis per share	$ 56.05	$ 56.05
GAAP Cost	$ 30,000,000	$ 30,000,000
Fair Value	30,210,000	30,210,000
Closing share price (in dollars per share)	$ 56.44	$ 56.44
Unrealized net loss	$ (2,425,000)	$ (996,000)

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

Balance held at close of period in number of shares.

+ References+ Details