Land Under Development - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) lot parcel
Real Estate [Abstract]
Number of raw parcels of land owned | parcel	4
Carrying value of raw parcels of land	$ 33,078
Number of finished lots expected to be developed from raw parcels of land | lot	450
Aggregate additional funding commitments related to raw land property under joint development	$ 7,400
Expected development credits that will offset the aggregate additional funding commitments related to raw land property development	$ 4,600