Net Income Attributable to Green Brick Partners, Inc. Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income attributable to Green Brick Partners, Inc.	$ 25,969	$ 15,917
Weighted-average number of shares outstanding —basic (in shares)	50,633	50,454
Basic net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.51	$ 0.32
Dilutive effect of stock options and restricted stock awards (in shares)	360	192
Weighted-average number of shares outstanding —diluted (in shares)	50,993	50,646
Diluted net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.51	$ 0.31