Investment In Unconsolidated Ventures - Additional Information (Detail)		3 Months Ended								12 Months Ended
		Dec. 31, 2017 USD ($) a property venture	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) property	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) a property venture	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of ventures under ownership interest using equity method | venture		15								15
Investment in unconsolidated ventures										$ 4,548,000	$ 6,089,000	$ 26,349,000
Distributions										34,439,000	13,419,000	24,909,000
Gain of sale of assets										113,411,000	166,747,000	1,585,000
Earnings (Loss)										39,150,000	9,119,000	59,320,000
Equity in earnings of unconsolidated ventures		$ 7,026,000	$ 1,764,000	$ 2,747,000	$ 6,362,000	$ 2,251,000	$ 3,637,000	$ 188,000	$ 47,000	17,899,000	6,123,000	16,008,000
Non-cash impairment charges										47,172,000	60,939,000	108,184,000
Fees for services										$ 741,000	2,466,000	1,856,000
Variable Interest Entity, Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Number of ventures that are a VIE | venture										0
CREA FMF
Schedule of Equity Method Investments [Line Items]
Distributions										$ 11,956,000
Net proceeds										71,750,000
Gain of sale of assets										$ 18,986,000
CREA FMF | Multi Family Property
Schedule of Equity Method Investments [Line Items]
Number of units of multifamily project | property		320								320
FMF Peakview
Schedule of Equity Method Investments [Line Items]
Net proceeds											13,917,000
Gain of sale of assets											$ 10,363,000
FMF Peakview | Multi Family Property
Schedule of Equity Method Investments [Line Items]
Number of units of multifamily project | property						304					304
Forestar Group Inc. | CREA FMF
Schedule of Equity Method Investments [Line Items]
Net proceeds										$ 7,783,000
242, LLC
Schedule of Equity Method Investments [Line Items]
Earnings (Loss)	[1],[2]									8,021,000	$ 1,259,000	9,588,000
Equity in earnings of unconsolidated ventures	[1],[2]									4,096,000	668,000	4,919,000
242, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Distributions										4,348,000
Net proceeds										$ 9,719,000
Area of land (in acres) | a		46								46
Earnings (Loss)										$ 6,612,000
Equity method investment, ownership percentage		50.00%								50.00%
Equity in earnings of unconsolidated ventures										$ 3,306,000
CL Realty
Schedule of Equity Method Investments [Line Items]
Earnings (Loss)										(1,155,000)	237,000	424,000
Equity in earnings of unconsolidated ventures										(578,000)	$ 119,000	$ 212,000
CL Realty | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Distributions										1,200,000
Net proceeds										$ 2,400,000
Equity method investment, ownership percentage		50.00%								50.00%
Non-cash impairment charges										$ 3,756,000

[1] Includes unamortized deferred gains on real estate contributed by us to ventures. We recognize deferred gains as income as real estate is sold to third parties. Deferred gains of $548,000 are reflected as a reduction to our investment in unconsolidated ventures at year-end 2017.

[2] Our share of venture earnings in 2016 includes reallocation of prior year cumulative losses incurred by the venture as a result of equity contribution by the venture partner in 2016