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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to Green Brick Partners, Inc.	$ 14,869	$ 7,689	$ 26,072	$ 13,886
Weighted-average number of shares outstanding —basic (in shares)	50,664	49,047	50,620	49,003
Basic net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.29	$ 0.16	$ 0.52	$ 0.28
Dilutive effect of stock options and restricted stock awards (in shares)	119	76	131	67
Weighted-average number of shares outstanding —diluted (in shares)	50,783	49,123	50,751	49,070
Diluted net income attributable to Green Brick Partners, Inc. per share (in dollars per share)	$ 0.29	$ 0.16	$ 0.51	$ 0.28