Joint Ventures - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Assets:
Cash	$ 262,428	$ 425,316	$ 387,462	$ 545,419
Land under development	62,327
Liabilities and equity:
Equity	1,299,139	1,239,165
Total liabilities and shareholders' equity	2,663,216	2,511,718
Consolidated Joint Venture
Assets:
Cash	1,210	990
Other assets	37	379
Land under development		380
Total assets	1,247	1,749
Liabilities and equity:
Accrued expenses	611	567
Equity	636	1,182
Total liabilities and shareholders' equity	$ 1,247	$ 1,749