Computation of (Loss) Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income (loss) attributable to The New Home Company Inc.	$ (16,150)		$ 2,459		$ 115		$ (640)		$ 10,471	$ 4,318	$ 1,517	$ 846	$ (14,216)		$ 17,152	$ 21,022
Denominator:
Basic weighted-average shares outstanding													20,703,967		20,849,736	20,685,386
Stock options and unvested restricted stock units													0		145,762	106,059
Diluted weighted-average shares outstanding													20,703,967		20,995,498	20,791,445
Basic earnings (loss) per share attributable to The New Home Company Inc.	$ (0.80)	[1]	$ 0.12	[1]	$ 0.01	[1]	$ (0.03)	[1]	$ 0.50	$ 0.21	$ 0.07	$ 0.04	$ (0.69)	[1]	$ 0.82	$ 1.02
Diluted earnings (loss) per share attributable to The New Home Company Inc.	$ (0.80)		$ 0.12	[1]	$ 0.01	[1]	$ (0.03)	[1]	$ 0.50	$ 0.21	$ 0.07	$ 0.04	$ (0.69)	[1]	$ 0.82	$ 1.01
Antidilutive stock options and unvested restricted stock units not included in diluted earnings per share													1,311,802		7,074	849,977

[1] (1)Some amounts do not add to our full year results presented on our consolidated statement of operations due to rounding differences in quarterly and annual weighted average share calculations