Investments in and Advances to Other Real Estate Partnerships - Condensed Combined Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Total Revenues	$ 74,746	$ 71,301	$ 148,181	$ 141,409
Property Expenses	(24,700)	(22,662)	(49,277)	(45,722)
Impairment of Real Estate			(1,605)	(1,101)
Depreciation and Other Amortization	(26,179)	(26,133)	(50,307)	(53,539)
Interest Income	621	697	1,207	1,643
Interest Expense	(17,284)	(19,695)	(34,932)	(40,904)
Amortization of Deferred Financing Costs	(788)	(799)	(1,590)	(1,622)
Loss from Retirement of Debt	(4,222)	(6,223)	(5,372)	(6,222)
Loss from Continuing Operations	(2,144)	(12,708)	(634)	(17,549)
Discontinued Operations:
Income (Loss) Attributable to Discontinued Operations	56	949	230	695
Loss on Sale of Real Estate	13,481	1,415	10,407	7,614
Income from Discontinued Operations	13,537	2,364	10,637	8,309
Net Income (Loss)	11,393	(10,344)	10,265	(9,240)
Other Real Estate Partnerships
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Total Revenues	9,941	10,258	19,741	20,294
Property Expenses	(3,074)	(2,911)	(6,250)	(5,911)
Impairment of Real Estate	0	0	0	172
Depreciation and Other Amortization	(3,059)	(3,351)	(6,109)	(7,636)
Interest Income	1,253	2,243	2,572	4,386
Interest Expense	(1,147)	(1,477)	(2,462)	(2,961)
Amortization of Deferred Financing Costs	(45)	(51)	(97)	(103)
Loss from Retirement of Debt	(214)	0	(214)	0
Loss from Continuing Operations	3,655	4,711	7,181	8,241
Discontinued Operations:
Income (Loss) Attributable to Discontinued Operations	0	64	0	(197)
Loss on Sale of Real Estate	0	(29)	0	(29)
Income from Discontinued Operations	0	35	0	(226)
Net Income (Loss)	$ 3,655	$ 4,746	$ 7,181	$ 8,015