Assets for Reportable Segment (Detail) - Parent Company [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 11,534,129	$ 11,604,491
Large Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,060,183	4,126,885
Secondary Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,741,902	1,768,183
Non-Same Store and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,550,019	5,479,780
Corporate assets
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 182,025	$ 229,643