Summary of Financial Position of Entities Accounted for using Equity Method (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets:
Real estate, net	$ 1,583,397	$ 1,393,274
Other assets	70,233	67,278
Total assets	1,653,630	1,460,552
Liabilities and partners' capital:
Mortgage notes payable and credit facility	1,074,429	965,931
Other liabilities	27,335	24,835
Partners' capital	551,866	469,786
Total liabilities and partners' capital	$ 1,653,630	$ 1,460,552