Real Estate - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Real Estate Properties [Line Items]
Costs relate to water, sewer and other infrastructure assets	$ 15,713,000	$ 4,345,000
Recovery of Direct Costs	(4,540,000)	(2,922,000)
Investment in resort development	509,467,000		517,150,000
Proceeds from sale of multifamily property	0	29,474,000
Outstanding debt assumed by buyer	96,915,000	46,374,000
Real Estate Investment Property, at Cost	80,381,000		100,855,000
Depreciation expense, related to commercial and income producing properties	1,927,000	2,736,000
Utility and Improvement District [Member]
Real Estate Properties [Line Items]
Cost of asset in developed and under development projects	63,795,000		50,476,000
Cibolo Canyons Project [Member]
Real Estate Properties [Line Items]
Collection related to reduction of investment in the mixed-use development	2,700,000	1,950,000
Investment in resort development	29,818,000
Consolidated Properties [Member]
Real Estate Properties [Line Items]
Recovery of Direct Costs	1,840,000	972,000
Multi Family Development Properties [Member]
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	30,367,000
San Antonio Texas [Member] | Cibolo Canyons Project [Member]
Real Estate Properties [Line Items]
Cost of asset in developed and under development projects	41,795,000
Austin, Texas [Member] | Hotel Property [Member]
Real Estate Properties [Line Items]
Commercial and income producing properties, investment unit	413
Real Estate Investment Property, at Cost	20,881,000
Austin, Texas [Member] | Multi Family Property [Member]
Real Estate Properties [Line Items]
Decrease in Commercial & income producing properties	29,707,000
Commercial and income producing properties commencing construction unit	289
Real estate property sale price	41,000,000
Proceeds from sale of multifamily property	21,522,000
Outstanding debt assumed by buyer	18,902,000
Gain on sale of assets	$ 10,881,000