Marketable Securities - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Investment Holdings [Line Items]
Change in fair value of marketable securities (see Note 7)	$ (5,170)	$ 0
Macerich Interest
Investment Holdings [Line Items]
Macerich common shares	535,265		535,265
Economic basis per share	$ 56.05
Economic cost	$ 30,000
Fair value	$ 29,986		$ 35,156
Closing share price	$ 56.02		$ 65.68
Change in fair value of marketable securities (see Note 7)	$ (5,170)

Economic basis per share of marketable securities

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

Amount of equity securities categorized neither as held-to-maturity nor as trading.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Balance held at close of period in number of shares.

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- Definition

The aggregate net change in the difference between the fair value and the carrying value, or in the comparative fair values, of marketable securities categorized as trading held at each balance sheet date, that was included in earnings for the period, which may have arisen from (a) securities classified as trading, (b) the unrealized holding gain (loss) on held-to-maturity securities transferred to the trading security category, and (c) the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) on available-for-sale securities transferred to trading securities during the period.

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- Definition

Price of a single share of a number of saleable stocks of a company.

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No definition available.

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