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, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income attributable to The New Home Company Inc.	$ 10,471		$ 4,318		$ 1,517		$ 846		$ 13,780	$ 5,547	$ 2,509	$ (814)	$ 17,152		$ 21,022	$ 21,688
Denominator:
Basic weighted-average shares outstanding													20,849,736		20,685,386	16,767,513
Stock options and unvested restricted stock units													145,762		106,059	173,575
Diluted weighted-average shares outstanding													20,995,498		20,791,445	16,941,088
Basic earnings per share attributable to The New Home Company Inc.	$ 0.50	[1]	$ 0.21	[1]	$ 0.07	[1]	$ 0.04	[1]	$ 0.67	$ 0.27	$ 0.12	$ (0.04)	$ 0.82	[1]	$ 1.02	$ 1.29
Diluted earnings per share attributable to The New Home Company Inc.	$ 0.50	[1]	$ 0.21	[1]	$ 0.07	[1]	$ 0.04	[1]	$ 0.66	$ 0.27	$ 0.12	$ (0.04)	$ 0.82	[1]	$ 1.01	$ 1.28
Antidilutive stock options and unvested restricted stock units not included in diluted earnings per share													7,074		849,977	7,414

[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