Recently Issued Accounting Literature - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to retained earnings	$ 274,977			$ 302,543
Change in fair value of marketable securities (see Note 7)	(5,170)	$ 0
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to retained earnings			$ 5,156
Macerich Interest
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in fair value of marketable securities (see Note 7)	$ (5,170)
Closing share price	$ 56.02			$ 65.68
Macerich Interest | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in fair value of marketable securities (see Note 7)	$ (5,170)