Investments in Unconsolidated Real Estate Entities - Schedule of Operation for Apartment LLCs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues
Rental	$ 89,368	$ 89,414	$ 177,029	$ 177,442
Other property revenues	5,789	5,389	11,246	10,654
Total revenues	95,431	95,026	188,862	188,538
Expenses
Property operating and maintenance	41,512	41,795	81,635	82,391
Interest	7,753	10,433	15,846	21,677
Total expenses	67,712	68,096	134,475	136,578
Net income	19,610	47,719	39,553	61,955
Company's share of net income in Apartment LLCs	568	501	965	986
Unconsolidated Properties [Member]
Revenues
Rental	6,856	6,635	13,640	13,120
Other property revenues	538	489	993	928
Total revenues	7,394	7,124	14,633	14,048
Expenses
Property operating and maintenance	3,049	2,830	6,156	5,581
Depreciation and amortization	1,464	1,387	2,912	2,763
Interest	2,258	2,258	4,496	4,496
Total expenses	6,771	6,475	13,564	12,840
Net income	623	649	1,069	1,208
Company's share of net income in Apartment LLCs	$ 568	$ 501	$ 965	$ 986