Schedule III - Consolidated Real Estate and Accumulated Depreciation (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 383,570
Buildings & Improvements		56,559
Improvements less Cost of Sales and Other		169,624
Carrying Costs	[1]	9,091
Land & Land Improvements		509,999
Buildings & Improvements		108,845
Total		618,844	$ 607,133	$ 547,530	$ 545,370
Accumulated depreciation		(32,129)	$ (31,377)	$ (28,066)	$ (28,220)
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		43,691
Entitled, developed and under development projects [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		283,025
Improvements less Cost of Sales and Other		60,025
Carrying Costs	[1]	9,091
Land & Land Improvements		352,141
Total		352,141
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		4,355
Entitled, developed and under development projects [Member] | Other County [Member] | Other Property [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		8,443
Improvements less Cost of Sales and Other		(4,097)
Carrying Costs	[1]	653
Land & Land Improvements		4,999
Total		4,999
Entitled, developed and under development projects [Member] | TENNESSEE | Williamson County [Member] | Morgan Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		6,841
Improvements less Cost of Sales and Other		(552)
Carrying Costs	[1]	166
Land & Land Improvements		6,455
Total		$ 6,455
Date of Construction		2013
Date Acquired		2013
Entitled, developed and under development projects [Member] | TENNESSEE | Williamson County [Member] | Vickery Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,575
Improvements less Cost of Sales and Other		560
Land & Land Improvements		4,135
Total		$ 4,135
Date Acquired		2015
Entitled, developed and under development projects [Member] | TENNESSEE | Williamson County [Member] | Weatherford Estates [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 856
Improvements less Cost of Sales and Other		1,603
Land & Land Improvements		2,459
Total		$ 2,459
Date of Construction		2015
Date Acquired		2014
Entitled, developed and under development projects [Member] | TENNESSEE | Williamson County [Member] | Beckwith Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 1,294
Improvements less Cost of Sales and Other		2,519
Land & Land Improvements		3,813
Total		$ 3,813
Date of Construction		2015
Date Acquired		2014
Entitled, developed and under development projects [Member] | ARIZONA | Pima County [Member] | Dove Mountain [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 5,860
Improvements less Cost of Sales and Other		3
Land & Land Improvements		5,863
Total		$ 5,863
Date Acquired		2015
Entitled, developed and under development projects [Member] | California [Member] | Contra Costa County [Member] | San Joaquin River [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 12,225
Improvements less Cost of Sales and Other		(3,310)
Land & Land Improvements		8,915
Total		8,915
Entitled, developed and under development projects [Member] | COLORADO | Douglas County [Member] | Pinery West [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		7,308
Improvements less Cost of Sales and Other		3,691
Land & Land Improvements		10,999
Total		$ 10,999
Date of Construction		2006
Date Acquired		2006
Entitled, developed and under development projects [Member] | COLORADO | Weld County [Member] | Buffalo Highlands [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,001
Improvements less Cost of Sales and Other		547
Land & Land Improvements		3,548
Total		$ 3,548
Date of Construction		2006
Date Acquired		2005
Entitled, developed and under development projects [Member] | COLORADO | Weld County [Member] | Johnstown Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 2,749
Improvements less Cost of Sales and Other		4,024
Carrying Costs	[1]	188
Land & Land Improvements		6,961
Total		$ 6,961
Date of Construction		2002
Date Acquired		2002
Entitled, developed and under development projects [Member] | COLORADO | Weld County [Member] | Stone Braker [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,878
Improvements less Cost of Sales and Other		(1,469)
Land & Land Improvements		2,409
Total		$ 2,409
Date of Construction		2005
Date Acquired		2005
Entitled, developed and under development projects [Member] | Georgia [Member] | Cobb County [Member] | West Oaks [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 1,669
Improvements less Cost of Sales and Other		232
Land & Land Improvements		1,901
Total		$ 1,901
Date of Construction		2015
Date Acquired		2015
Entitled, developed and under development projects [Member] | Georgia [Member] | Paulding County [Member] | Harris Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 265
Improvements less Cost of Sales and Other		(111)
Land & Land Improvements		154
Total		$ 154
Date Acquired		2012
Entitled, developed and under development projects [Member] | Georgia [Member] | Paulding County [Member] | Seven Hills [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 2,964
Improvements less Cost of Sales and Other		145
Land & Land Improvements		3,109
Total		$ 3,109
Date Acquired		2012
Entitled, developed and under development projects [Member] | South Carolina [Member] | York County [Member] | Habersham [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,877
Improvements less Cost of Sales and Other		3,072
Carrying Costs	[1]	239
Land & Land Improvements		7,188
Total		$ 7,188
Date of Construction		2014
Date Acquired		2013
Entitled, developed and under development projects [Member] | South Carolina [Member] | Lancaster County [Member] | Ansley [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 5,089
Improvements less Cost of Sales and Other		574
Land & Land Improvements		5,663
Total		$ 5,663
Date Acquired		2015
Entitled, developed and under development projects [Member] | North Carolina [Member] | Mechlanburg County [Member] | Walden [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 12,085
Improvements less Cost of Sales and Other		345
Land & Land Improvements		12,430
Total		$ 12,430
Date Acquired		2015
Entitled, developed and under development projects [Member] | Texas [Member] | Hays County [Member] | Arrowhead Ranch [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 12,856
Improvements less Cost of Sales and Other		6,537
Land & Land Improvements		19,393
Total		$ 19,393
Date of Construction		2015
Date Acquired		2007
Entitled, developed and under development projects [Member] | Texas [Member] | Williamson County [Member] | La Conterra [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 4,024
Improvements less Cost of Sales and Other		(2,790)
Carrying Costs	[1]	293
Land & Land Improvements		1,527
Total		$ 1,527
Date Acquired		2006
Entitled, developed and under development projects [Member] | Texas [Member] | Williamson County [Member] | Westside at Buttercup Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 13,149
Improvements less Cost of Sales and Other		(13,586)
Carrying Costs	[1]	488
Land & Land Improvements		51
Total		$ 51
Date of Construction		1993
Date Acquired		1993
Entitled, developed and under development projects [Member] | Texas [Member] | Tarrant County [Member] | Summer Creek Ranch [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 2,887
Improvements less Cost of Sales and Other		(1,601)
Land & Land Improvements		1,286
Total		$ 1,286
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Tarrant County [Member] | Bar C Ranch [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 1,365
Improvements less Cost of Sales and Other		3,258
Carrying Costs	[1]	32
Land & Land Improvements		4,655
Total		$ 4,655
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Nueces County [Member] | Tortuga Dunes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 12,080
Improvements less Cost of Sales and Other		9,670
Land & Land Improvements		21,750
Total		$ 21,750
Date Acquired		2006
Entitled, developed and under development projects [Member] | Texas [Member] | Calhoun County [Member] | Caracol [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 8,603
Improvements less Cost of Sales and Other		3,688
Carrying Costs	[1]	2,047
Land & Land Improvements		14,338
Total		$ 14,338
Date of Construction		2006
Date Acquired		2006
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		$ 2,237
Entitled, developed and under development projects [Member] | Texas [Member] | Bastrop County [Member] | Hunters Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		3,613
Improvements less Cost of Sales and Other		5,180
Carrying Costs	[1]	358
Land & Land Improvements		9,151
Total		$ 9,151
Date of Construction		2001
Date Acquired		2001
Entitled, developed and under development projects [Member] | Texas [Member] | Bastrop County [Member] | The Colony [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 8,726
Improvements less Cost of Sales and Other		15,206
Carrying Costs	[1]	161
Land & Land Improvements		24,093
Total		$ 24,093
Date of Construction		1999
Date Acquired		1999
Entitled, developed and under development projects [Member] | Texas [Member] | Bexar County [Member] | Cibolo Canyons [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 17,305
Improvements less Cost of Sales and Other		40,243
Carrying Costs	[1]	1,202
Land & Land Improvements		58,750
Total		$ 58,750
Date of Construction		2004
Date Acquired		1986
Entitled, developed and under development projects [Member] | Texas [Member] | Harris County [Member] | City Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,946
Improvements less Cost of Sales and Other		1,463
Carrying Costs	[1]	1,641
Land & Land Improvements		7,050
Total		$ 7,050
Date of Construction		2002
Date Acquired		2001
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		$ 1,659
Entitled, developed and under development projects [Member] | Texas [Member] | Harris County [Member] | Barrington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		8,950
Improvements less Cost of Sales and Other		(7,062)
Land & Land Improvements		1,888
Total		$ 1,888
Date Acquired		2011
Entitled, developed and under development projects [Member] | Texas [Member] | Harris County [Member] | Imperial Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 5,345
Improvements less Cost of Sales and Other		819
Land & Land Improvements		6,164
Total		$ 6,164
Date of Construction		2015
Date Acquired		2014
Entitled, developed and under development projects [Member] | Texas [Member] | Collin County [Member] | Lakes Of Prosper [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 8,951
Improvements less Cost of Sales and Other		(3,550)
Carrying Costs	[1]	180
Land & Land Improvements		5,581
Total		$ 5,581
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Collin County [Member] | Maxwell Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 9,904
Improvements less Cost of Sales and Other		(7,946)
Carrying Costs	[1]	635
Land & Land Improvements		2,593
Total		$ 2,593
Date of Construction		2000
Date Acquired		2000
Entitled, developed and under development projects [Member] | Texas [Member] | Collin County [Member] | Park Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 2,177
Improvements less Cost of Sales and Other		3,661
Land & Land Improvements		5,838
Total		$ 5,838
Date of Construction		2014
Date Acquired		2013
Entitled, developed and under development projects [Member] | Texas [Member] | Collin County [Member] | Timber Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 7,282
Improvements less Cost of Sales and Other		9,137
Land & Land Improvements		16,419
Total		$ 16,419
Date of Construction		2007
Date Acquired		2007
Entitled, developed and under development projects [Member] | Texas [Member] | Collin County [Member] | Village Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 4,772
Improvements less Cost of Sales and Other		(4,765)
Carrying Costs	[1]	45
Land & Land Improvements		52
Total		$ 52
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Comal County [Member] | Oak Creek Estates [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 1,921
Improvements less Cost of Sales and Other		2,314
Carrying Costs	[1]	175
Land & Land Improvements		4,410
Total		$ 4,410
Date of Construction		2006
Date Acquired		2005
Entitled, developed and under development projects [Member] | Texas [Member] | Dallas County [Member] | Stoney Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 12,822
Improvements less Cost of Sales and Other		2,783
Carrying Costs	[1]	49
Land & Land Improvements		15,654
Total		$ 15,654
Date of Construction		2007
Date Acquired		2007
Entitled, developed and under development projects [Member] | Texas [Member] | Denton County [Member] | Lantana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 27,673
Improvements less Cost of Sales and Other		(7,382)
Land & Land Improvements		20,291
Total		$ 20,291
Date of Construction		2000
Date Acquired		1999
Entitled, developed and under development projects [Member] | Texas [Member] | Denton County [Member] | River's Edge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 1,227
Improvements less Cost of Sales and Other		381
Land & Land Improvements		1,608
Total		$ 1,608
Date Acquired		2014
Entitled, developed and under development projects [Member] | Texas [Member] | Denton County [Member] | The Preserve At Pecan Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 5,855
Improvements less Cost of Sales and Other		(3,905)
Carrying Costs	[1]	436
Land & Land Improvements		2,386
Total		$ 2,386
Date of Construction		2006
Date Acquired		2005
Entitled, developed and under development projects [Member] | Texas [Member] | Fort Bend County [Member] | Summer Lakes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 4,269
Improvements less Cost of Sales and Other		968
Land & Land Improvements		5,237
Total		$ 5,237
Date of Construction		2013
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Fort Bend County [Member] | Summer Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 4,804
Improvements less Cost of Sales and Other		57
Land & Land Improvements		4,861
Total		$ 4,861
Date of Construction		2013
Date Acquired		2012
Entitled, developed and under development projects [Member] | Texas [Member] | Fort Bend County [Member] | Willow Creek Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,479
Improvements less Cost of Sales and Other		(311)
Carrying Costs	[1]	90
Land & Land Improvements		3,258
Total		$ 3,258
Date of Construction		2012
Date Acquired		2012
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		$ 459
Entitled, developed and under development projects [Member] | Missouri [Member] | Clay County [Member] | Somerbrook [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		3,061
Improvements less Cost of Sales and Other		(218)
Carrying Costs	[1]	13
Land & Land Improvements		2,856
Total		$ 2,856
Date of Construction		2003
Date Acquired		2001
Undeveloped Land Type [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 61,742
Improvements less Cost of Sales and Other		36,439
Carrying Costs	[1]	0
Land & Land Improvements		98,181
Total		98,181
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		0
Undeveloped Land Type [Member] | Other County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		9,170
Improvements less Cost of Sales and Other		7,661
Land & Land Improvements		16,831
Total		16,831
Undeveloped Land Type [Member] | California [Member] | Los Angeles [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		3,950
Improvements less Cost of Sales and Other		19,564
Land & Land Improvements		23,514
Total		$ 23,514
Date Acquired		1997
Undeveloped Land Type [Member] | Georgia [Member] | Coweta County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 3,089
Improvements less Cost of Sales and Other		1,343
Land & Land Improvements		4,432
Total		4,432
Undeveloped Land Type [Member] | Georgia [Member] | Dawson County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		2,228
Improvements less Cost of Sales and Other		3,381
Land & Land Improvements		5,609
Total		5,609
Undeveloped Land Type [Member] | Georgia [Member] | Dawson County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		3,150
Improvements less Cost of Sales and Other		(108)
Land & Land Improvements		3,042
Total		3,042
Undeveloped Land Type [Member] | Georgia [Member] | Polk County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		2,354
Improvements less Cost of Sales and Other		(198)
Land & Land Improvements		2,156
Total		2,156
Undeveloped Land Type [Member] | Georgia [Member] | Bexar County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Improvements less Cost of Sales and Other		3,036
Land & Land Improvements		3,036
Total		3,036
Undeveloped Land Type [Member] | Georgia [Member] | Harris County [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		685
Improvements less Cost of Sales and Other		1,151
Land & Land Improvements		1,836
Total		1,836
Undeveloped Land Type [Member] | Georgia [Member] | Bartow County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		4,057
Improvements less Cost of Sales and Other		(2,440)
Land & Land Improvements		1,617
Total		1,617
Undeveloped Land Type [Member] | Georgia [Member] | Carroll County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		13,564
Improvements less Cost of Sales and Other		2,580
Land & Land Improvements		16,144
Total		16,144
Undeveloped Land Type [Member] | Georgia [Member] | Cherokee County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		6,043
Improvements less Cost of Sales and Other		536
Land & Land Improvements		6,579
Total		6,579
Undeveloped Land Type [Member] | Georgia [Member] | Gilmer County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		2,748
Improvements less Cost of Sales and Other		(62)
Land & Land Improvements		2,686
Total		2,686
Undeveloped Land Type [Member] | Georgia [Member] | Haralson County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		195
Improvements less Cost of Sales and Other		88
Land & Land Improvements		283
Total		283
Undeveloped Land Type [Member] | Georgia [Member] | Lumpkin County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		3,015
Improvements less Cost of Sales and Other		(93)
Land & Land Improvements		2,922
Total		2,922
Undeveloped Land Type [Member] | Georgia [Member] | Paulding County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 7,494
Improvements less Cost of Sales and Other
Land & Land Improvements		$ 7,494
Total		7,494
Income Producing Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		38,803
Buildings & Improvements		56,559
Improvements less Cost of Sales and Other		73,160
Carrying Costs	[1]	0
Land & Land Improvements		59,677
Buildings & Improvements		108,845
Total		168,522
Accumulated depreciation		(32,129)
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		39,336
Income Producing Properties [Member] | TENNESSEE | Davidson County [Member] | Westmont [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		6,607
Improvements less Cost of Sales and Other		3,340
Land & Land Improvements		9,947
Total		$ 9,947
Date Acquired		2014
Income Producing Properties [Member] | North Carolina [Member] | Mechlanburg County [Member] | East Morehead [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 5,779
Improvements less Cost of Sales and Other		14,208
Land & Land Improvements		19,987
Total		$ 19,987
Date Acquired		2012
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | Radisson Hotel And Suites [Member]
Real Estate and Accumulated Depreciation [Line Items]
Buildings & Improvements		$ 10,603
Improvements less Cost of Sales and Other		52,286
Land & Land Improvements		0
Buildings & Improvements		62,889
Total		62,889
Accumulated depreciation		(29,268)
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		15,400
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | Eleven [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		7,940
Buildings & Improvements		45,956
Improvements less Cost of Sales and Other		0
Land & Land Improvements		7,940
Buildings & Improvements		45,956
Total		53,896
Accumulated depreciation		$ (2,861)
Date of Construction		2013
Date Acquired		2014
SEC Schedule III, Real Estate and Accumulated Depreciation, Amount of Encumbrances		$ 23,936
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | Downtown Edge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		11,202
Improvements less Cost of Sales and Other		1,504
Land & Land Improvements		12,706
Total		$ 12,706
Date Acquired		2014
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | West Austin [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land		$ 7,275
Improvements less Cost of Sales and Other		1,822
Land & Land Improvements		9,097
Total		$ 9,097
Date Acquired		2014

[1] Includes natural gas liquids (NGLs).