Net Income Attributable to Green Brick Partners, Inc. Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to Green Brick Partners, Inc.	$ 12,197	$ 9,280	$ 38,269	$ 23,165
Weighted-average number of shares outstanding —basic (in shares)	50,686	49,808	50,642	49,274
Basic net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.24	$ 0.19	$ 0.76	$ 0.47
Dilutive effect of stock options and restricted stock awards (in shares)	92	84	118	73
Weighted-average number of shares outstanding —diluted (in shares)	50,778	49,892	50,760	49,347
Diluted net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.24	$ 0.19	$ 0.75	$ 0.47