Variable Interest Entities - Total Risk of Loss Related to Contract Land Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure [Abstract]
Contract land deposits	$ 400,428	$ 411,150
Loss reserve on contract land deposits	(29,999)	(31,306)
Contract land deposits, net	370,429	379,844
Contingent obligations in the form of letters of credit	1,996	2,379
Contingent specific performance obligations	1,505	1,505
Total risk of loss	$ 373,930	$ 383,728