Quarterly Results (unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Supplemental Income Statement Elements [Abstract]

Summary of the unaudited quarterly financial information

A summary of the unaudited quarterly financial information for the years ended December 31, 2012 and 2011 is presented below:

	2012 Quarter Ended
	March 31			June 30			September 30			December 31
Equity in income of joint ventures	$	75,814		$	79,832		$	3,269		$	(4,588	)
Interest and other income	$	3,425		$	1,785		$	1,326		$	1,370
Net income (loss)	$	21,656		$	37,490		$	(37,700	)	$	(43,513	)
Net income (loss) allocated to:
Class A limited partners	$	79,177		$	(110,819	)	$	(37,323	)	$	(43,078	)
Class B limited partners	$	(57,738	)	$	147,934		$	—		$	—
General partners	$	217		$	375		$	(377	)	$	(435	)
Net income (loss) per weighted-average limited partner unit:
Class A	$	0.02		$	(0.03	)	$	(0.01	)	$	(0.01	)
Class B(a)	$	(0.26	)	$	0.65		$	—		$	—
Distribution of operating cash per weighted-average limited   partner unit:
Class A	$	—		$	—		$	—		$	—
Class B	$	—		$	—		$	—		$	—
Distribution of net property sale proceeds per weighted-   average limited partner unit:
Class A	$	—		$	0.99		$	—		$	—
Class B	$	—		$	1.11		$	—		$	—

	2011 Quarter Ended
	March 31			June 30		September 30			December 31
Equity in income of joint ventures	$	48,095		$	540,268	$	59,833		$	72,298
Interest and other income	$	1,747		$	2,271	$	3,870		$	3,153
Net income (loss)	$	(14,133	)	$	501,846	$	27,592		$	38,171
Net income (loss) allocated to:
Class A limited partners	$	75,276		$	221,677	$	87,713		$	90,493
Class B limited partners	$	(89,409	)	$	279,946	$	(60,404	)	$	(52,703	)
General partners	$	—		$	223	$	283		$	381
Net income (loss) per weighted-average limited partner unit:
Class A	$	0.02		$	0.07	$	0.03		$	0.03
Class B	$	(0.38	)	$	1.19	$	(0.26	)	$	(0.22	)
Distribution of operating cash per weighted-average limited   partner unit:
Class A	$	—		$	—	$	—		$	—
Class B	$	—		$	—	$	—		$	—
Distribution of net property sale proceeds per weighted-   average limited partner unit:
Class A	$	—		$	—	$	—		$	—
Class B	$	—		$	—	$	—		$	—

^(a) The quarterly per-unit amounts have been calculated using actual income (loss) for the respective quarters. Conversely, the corresponding annual income (loss) per-unit amounts have been calculated assuming that income (loss) was earned ratably over the year. As a result, the sum of these quarterly per-unit amounts does not equal the respective annual per-unit amount presented in the accompanying financial statements.