Variable Interest Entities ("VIEs") - Total Risk of Loss Related to Contract Land Deposits (Detail) $ in Thousands	Sep. 30, 2018 USD ($) lot	Dec. 31, 2017 USD ($) lot
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure [Abstract]
Contract land deposits	$ 402,318	$ 400,428
Loss reserve on contract land deposits	(27,968)	(29,999)
Contract land deposits, net	374,350	370,429
Contingent obligations in the form of letters of credit	3,870	1,996
Specific performance obligations	1,505	1,505
Total risk of loss	$ 379,725	$ 373,930
Finished lots committed to purchase under specific performance obligations | lot	10	10