Consolidated Statement of Changes in Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional Capital	Retained Earnings	Treasury Stock	Alexander's Equity	Non-controlling Interest
Balance, at Dec. 31, 2008	$ 180,751	$ 5,173	$ 30,647	$ 143,731	$ (455)	$ 179,096	$ 1,655
Shares Issued, Beginning Balance at Dec. 31, 2008		5,173,000
Net income	132,941			132,190		132,190	751
Common stock issued under option plan	934		854		80	934
Balance, at Dec. 31, 2009	314,626	5,173	31,501	275,921	(375)	312,220	2,406
Shares Issued, Ending Balance at Dec. 31, 2009		5,173,000
Net income	67,445			66,429		66,429	1,016
Dividends paid	(38,295)			(38,295)		(38,295)
Balance, at Dec. 31, 2010	343,776	5,173	31,501	304,055	(375)	340,354	3,422
Shares Issued, Ending Balance at Dec. 31, 2010	5,173,450	5,173,000
Net income	81,046			79,423		79,423	1,623
Dividends paid	(61,277)			(61,277)		(61,277)
Distributions	(600)						(600)
Deferred stock unit grant	300		300			300
Balance, at Dec. 31, 2011	$ 363,245	$ 5,173	$ 31,801	$ 322,201	$ (375)	$ 358,800	$ 4,445
Shares Issued, Ending Balance at Dec. 31, 2011	5,173,450	5,173,000