Commitments and Contingencies - Minto Communities - Additional Information (Detail)	Sep. 30, 2015 ft² a Property
Loss Contingencies [Line Items]
Area of real estate property | ft²	1,270,000
Definitive Sales Contracts [Member] | Minto Communities [Member]
Loss Contingencies [Line Items]
Number of units planned on definitive sales contracts | Property	3,400
Area of real estate property	1,600