Commitments and Contingencies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Apartment Property Community	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Commitments And Contingencies [Line Items]
Rent expense	$ 3,914	$ 3,639	$ 3,542
Number of real estate properties | Property	61
Number of units in real estate property | Apartment	24,162
Communities Under Construction
Commitments And Contingencies [Line Items]
Number of real estate properties | Property	6
Number of units in real estate property | Apartment	2,290
Estimated total cost of constructions under development	$ 478,600
Estimated remaining cost of constructions	$ 327,300
Land Lease Communities [Member]
Commitments And Contingencies [Line Items]
Number of operating communities | Community	1
Ground Lease [Member]
Commitments And Contingencies [Line Items]
Lease expiration term	2074