Net Income Attributable to Green Brick Partners, Inc. Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income attributable to Green Brick Partners, Inc.	$ 52,263	$ 33,647	$ 78,232	$ 49,564
Weighted-average number of shares outstanding —basic (in shares)	50,701	50,583	50,667	50,519
Basic net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 1.03	$ 0.67	$ 1.54	$ 0.98
Dilutive effect of stock options and restricted stock awards (in shares)	363	109	362	150
Weighted-average number of shares outstanding —diluted (in shares)	51,064	50,692	51,029	50,669
Diluted net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 1.02	$ 0.66	$ 1.53	$ 0.98