Equity - Reconciliation of Changes in Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 709,742
Consolidated net income (loss)	$ (164,331)	$ 5,239	(206,886)	$ 28,994
Distributions to noncontrolling interests			(703)
Other (primarily share-based compensation)			6,252
Ending balance	508,405		508,405
Forestar Group Inc. [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			707,202
Consolidated net income (loss)			(206,881)
Distributions to noncontrolling interests			0
Other (primarily share-based compensation)			6,252
Ending balance	506,573		506,573
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			2,540
Consolidated net income (loss)			(5)
Distributions to noncontrolling interests			(703)
Other (primarily share-based compensation)			0
Ending balance	$ 1,832		$ 1,832