Land Under Development - Additional Information (Detail) $ in Thousands	Sep. 30, 2018 USD ($) parcel lot
Real Estate [Abstract]
Number of raw parcels of land owned | parcel	3
Carrying value of raw parcels of land	$ 36,064
Number of finished lots expected to be developed from raw parcels of land | lot	500
Aggregate additional funding commitments related to raw land property under joint development	$ 7,900
Expected development credits that will offset the aggregate additional funding commitments related to raw land property development	$ 4,700