Schedule III - Consolidated Real Estate and Accumulated Depreciation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 62,396
Land	389,035
Buildings & Improvements	57,996
Improvements less Cost of Sales and Other	150,128
Carrying Costs	9,974	[1]
Land & Land Improvements	468,521
Buildings & Improvements	138,612
Total	607,133		547,530	545,370	592,322
Accumulated depreciation	(31,377)		(28,066)	(28,220)	(26,955)
Entitled Developed and Under Development Projects [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	3,943
Land	290,166
Improvements less Cost of Sales and Other	21,133
Carrying Costs	9,974	[1]
Land & Land Improvements	321,273
Total	321,273
Entitled Developed and Under Development Projects [Member] | Other Country [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	32,304
Improvements less Cost of Sales and Other	(22,418)
Carrying Costs	1,271	[1]
Land & Land Improvements	11,157
Total	11,157
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	7,045
Land & Land Improvements	14,353
Total	14,353
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	555
Land & Land Improvements	3,556
Total	3,556
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	2,046
Carrying Costs	188	[1]
Land & Land Improvements	4,983
Total	4,983
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	(1,436)
Land & Land Improvements	2,442
Total	2,442
Date of Construction	2005
Date Acquired	2005
Entitled Developed and Under Development Projects [Member] | Georgia [Member] | Coweta County [Member] | Corinth Landing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	607
Improvements less Cost of Sales and Other	585
Land & Land Improvements	1,192
Total	1,192
Entitled Developed and Under Development Projects [Member] | Georgia [Member] | Coweta County [Member] | Coweta South Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	532
Improvements less Cost of Sales and Other	476
Land & Land Improvements	1,008
Total	1,008
Entitled Developed and Under Development Projects [Member] | Georgia [Member] | Coweta County [Member] | Genesee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	480
Improvements less Cost of Sales and Other	1,176
Land & Land Improvements	1,656
Total	1,656
Entitled Developed and Under Development Projects [Member] | Georgia [Member] | Dawson County [Member] | Woodlands At Burt Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	71
Improvements less Cost of Sales and Other	1,670
Land & Land Improvements	1,741
Total	1,741
Entitled Developed and Under Development Projects [Member] | Georgia [Member] | Cherokee County [Member] | Heron Pond [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	1,104
Improvements less Cost of Sales and Other	1,285
Land & Land Improvements	2,389
Total	2,389
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	129
Land & Land Improvements	3,093
Total	3,093
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	1,478
Carrying Costs	239	[1]
Land & Land Improvements	5,594
Total	5,594
Date Acquired	2013
Entitled Developed and Under Development Projects [Member] | Tennessee [Member] | Williamson County [Member] | Morgan Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	6,841
Improvements less Cost of Sales and Other	917
Carrying Costs	166	[1]
Land & Land Improvements	7,924
Total	7,924
Date Acquired	2013
Entitled Developed and Under Development Projects [Member] | Tennessee [Member] | Williamson County [Member] | Weatherford Estates [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	856
Improvements less Cost of Sales and Other	201
Land & Land Improvements	1,057
Total	1,057
Date Acquired	2014
Entitled Developed and Under Development Projects [Member] | Tennessee [Member] | Wilson County [Member] | Beckwith Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	1,294
Improvements less Cost of Sales and Other	185
Land & Land Improvements	1,479
Total	1,479
Date Acquired	2014
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	6,465
Carrying Costs	358	[1]
Land & Land Improvements	10,436
Total	10,436
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	12,347
Carrying Costs	161	[1]
Land & Land Improvements	21,234
Total	21,234
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	25,569
Improvements less Cost of Sales and Other	26,137
Carrying Costs	1,607	[1]
Land & Land Improvements	53,313
Total	53,313
Date of Construction	2004
Date Acquired	1986
Entitled Developed and Under Development Projects [Member] | Texas [Member] | Calhoun County [Member] | Caracol [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	3,869
Land	8,603
Improvements less Cost of Sales and Other	3,355
Carrying Costs	2,047	[1]
Land & Land Improvements	14,005
Total	14,005
Date of Construction	2006
Date Acquired	2006
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	(634)
Carrying Costs	180	[1]
Land & Land Improvements	8,497
Total	8,497
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	(8,687)
Carrying Costs	635	[1]
Land & Land Improvements	1,852
Total	1,852
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	1,294
Land & Land Improvements	3,471
Total	3,471
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	4,386
Land & Land Improvements	11,668
Total	11,668
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	6,550
Improvements less Cost of Sales and Other	(6,579)
Carrying Costs	81	[1]
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	941
Carrying Costs	175	[1]
Land & Land Improvements	3,037
Total	3,037
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	1,278
Carrying Costs	49	[1]
Land & Land Improvements	14,149
Total	14,149
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	(825)
Land & Land Improvements	26,848
Total	26,848
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	351
Land & Land Improvements	1,578
Total	1,578
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	(1,884)
Carrying Costs	436	[1]
Land & Land Improvements	4,407
Total	4,407
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	(169)
Land & Land Improvements	4,100
Total	4,100
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	3
Land & Land Improvements	4,807
Total	4,807
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	358
Carrying Costs	90	[1]
Land & Land Improvements	3,927
Total	3,927
Date Acquired	2012
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	(5,833)
Land & Land Improvements	3,117
Total	3,117
Date Acquired	2011
Entitled Developed and Under Development Projects [Member] | Texas [Member] | Harris County [Member] | City Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	74
Land	3,946
Improvements less Cost of Sales and Other	(1,485)
Carrying Costs	1,641	[1]
Land & Land Improvements	4,102
Total	4,102
Date of Construction	2002
Date Acquired	2001
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	47
Land & Land Improvements	5,392
Total	5,392
Date Acquired	2014
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	3,104
Land & Land Improvements	15,960
Total	15,960
Date Acquired	2007
Entitled Developed and Under Development Projects [Member] | Texas [Member] | Hood County [Member] | Harbor Lakes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	3,514
Improvements less Cost of Sales and Other	(1,970)
Carrying Costs	312	[1]
Land & Land Improvements	1,856
Total	1,856
Date of Construction	2000
Date Acquired	1998
Entitled Developed and Under Development Projects [Member] | Texas [Member] | Montgomery County [Member] | Woodtrace [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	8,622
Improvements less Cost of Sales and Other	(8,621)
Land & Land Improvements	1
Total	1
Date Acquired	2014
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	9,473
Land & Land Improvements	21,553
Total	21,553
Date Acquired	2006
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	(1,625)
Land & Land Improvements	1,262
Total	1,262
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	2,330
Land & Land Improvements	3,727
Total	3,727
Date Acquired	2012
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	293	[1]
Land & Land Improvements	1,527
Total	1,527
Date Acquired	2006
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	13	[1]
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	57,541
Improvements less Cost of Sales and Other	35,641
Land & Land Improvements	93,182
Total	93,182
Undeveloped Land Type [Member] | California [Member] | Los Angeles [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	3,969
Improvements less Cost of Sales and Other	18,122
Land & Land Improvements	22,091
Total	22,091
Date Acquired	1997
Undeveloped Land Type [Member] | Georgia [Member] | Coweta County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	454
Improvements less Cost of Sales and Other	380
Land & Land Improvements	834
Total	834
Undeveloped Land Type [Member] | Georgia [Member] | Coweta County [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	644
Improvements less Cost of Sales and Other	222
Land & Land Improvements	866
Total	866
Undeveloped Land Type [Member] | Georgia [Member] | Dawson County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	2,157
Improvements less Cost of Sales and Other	1,485
Land & Land Improvements	3,642
Total	3,642
Undeveloped Land Type [Member] | Georgia [Member] | Bartow County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	3,551
Improvements less Cost of Sales and Other	48
Land & Land Improvements	3,599
Total	3,599
Undeveloped Land Type [Member] | Georgia [Member] | Carroll County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	4,397
Improvements less Cost of Sales and Other	107
Land & Land Improvements	4,504
Total	4,504
Undeveloped Land Type [Member] | Georgia [Member] | Carroll County [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	9,006
Improvements less Cost of Sales and Other	2,159
Land & Land Improvements	11,165
Total	11,165
Undeveloped Land Type [Member] | Georgia [Member] | Cherokee County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	3,322
Improvements less Cost of Sales and Other	92
Land & Land Improvements	3,414
Total	3,414
Undeveloped Land Type [Member] | Georgia [Member] | Cherokee County [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	2,340
Improvements less Cost of Sales and Other	566
Land & Land Improvements	2,906
Total	2,906
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	26
Land & Land Improvements	2,774
Total	2,774
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	4
Land & Land Improvements	3,019
Total	3,019
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
Undeveloped Land Type [Member] | Georgia [Member] | Pickens County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	2,235
Improvements less Cost of Sales and Other	28
Land & Land Improvements	2,263
Total	2,263
Undeveloped Land Type [Member] | Georgia [Member] | Polk County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	2,354
Land & Land Improvements	2,354
Total	2,354
Undeveloped Land Type [Member] | Texas [Member] | Bexar County [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Improvements less Cost of Sales and Other	3,038
Land & Land Improvements	3,038
Total	3,038
Undeveloped Land Type [Member] | Texas [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	1,145
Land & Land Improvements	1,830
Total	1,830
Undeveloped Land Type [Member] | Texas [Member] | Other Country [Member] | Undeveloped Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	8,666
Improvements less Cost of Sales and Other	8,171
Land & Land Improvements	16,837
Total	16,837
Undeveloped Land Type [Member] | Texas [Member] | Other Country [Member] | Land In Entitlement Process [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	504
Improvements less Cost of Sales and Other	48
Land & Land Improvements	552
Total	552
Income Producing Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	58,453
Land	41,328
Buildings & Improvements	57,996
Improvements less Cost of Sales and Other	93,354
Carrying Costs	0	[1]
Land & Land Improvements	54,066
Buildings & Improvements	138,612
Total	192,678
Accumulated depreciation	(31,377)
Income Producing Properties [Member] | Tennessee [Member] | Davidson County [Member] | Westmont [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	6,607
Improvements less Cost of Sales and Other	1,068
Land & Land Improvements	7,675
Total	7,675
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	9,424
Land & Land Improvements	15,203
Total	15,203
Date Acquired	2012
Income Producing Properties [Member] | Texas [Member] | Dallas County [Member] | Cedar Hill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	19,117
Land	2,526
Improvements less Cost of Sales and Other	30,767
Land & Land Improvements	2,526
Buildings & Improvements	30,767
Total	33,293
Accumulated depreciation	231
Date of Construction	2011
Date Acquired	2011
Income Producing Properties [Member] | Texas [Member] | Hood County [Member] | Harbor Lakes Golf Club [Member]
Real Estate and Accumulated Depreciation [Line Items]
Buildings & Improvements	1,446
Improvements less Cost of Sales and Other	608
Buildings & Improvements	2,054
Total	2,054
Accumulated depreciation	(1,508)
Date of Construction	2000
Date Acquired	1998
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | Radisson Hotel And Suites [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	15,400
Buildings & Improvements	10,603
Improvements less Cost of Sales and Other	49,170
Land & Land Improvements	0
Buildings & Improvements	59,773
Total	59,773
Accumulated depreciation	(29,062)
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | Eleven [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	23,936
Land	7,940
Buildings & Improvements	45,947
Improvements less Cost of Sales and Other	71
Land & Land Improvements	7,940
Buildings & Improvements	46,018
Total	53,958
Accumulated depreciation	576
Date of Construction	2013
Date Acquired	2014
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	654
Land & Land Improvements	11,856
Total	11,856
Date Acquired	2014
Income Producing Properties [Member] | Texas [Member] | Travis County [Member] | West Austin [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land	7,274
Improvements less Cost of Sales and Other	1,592
Land & Land Improvements	8,866
Total	$ 8,866
Date Acquired	2014

[1] Includes natural gas liquids (NGLs).