Joint Ventures - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Assets:
Cash	$ 318,982	$ 425,316	$ 532,513	$ 545,419
Land under development	163,826
Liabilities and equity:
Equity	1,256,463	1,239,165
Total liabilities and shareholders' equity	2,541,651	2,511,718
Consolidated Joint Venture
Assets:
Cash	995	990
Other assets	326	379
Land under development	410	380
Total assets	1,731	1,749
Liabilities and equity:
Accrued expenses	858	567
Equity	873	1,182
Total liabilities and shareholders' equity	$ 1,731	$ 1,749