Accounts payable and accrued expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Payables And Accruals [Abstract]
Accounts payable	$ 6,064	$ 259
Accrued property taxes	30,163	4,760
Other accrued liabilities	17,980	1,473
Accrued construction liabilities	15,996	3,059
Resident security deposits	21,434	1,731
Total	$ 91,637	$ 11,282