Note 18 - Supplemental Guarantor Information - Supplemental Condensed Consolidating Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Revenue									$ 669,349	$ 667,566	$ 751,166
Cost of Sales:
Cost of Sales									616,207	605,666	660,240
Cost of sales, impairments									10,200	10,000	2,200
Gross Margin:
Gross margin									53,142	61,900	90,926
Selling and marketing expenses									(36,357)	(36,065)	(32,702)
General and administrative expenses									(25,723)	(25,966)	(26,330)
Equity in net income (loss) of unconsolidated joint ventures									(3,503)	(19,653)	866
Equity in net loss of subsidiaries									0	0	0
Gain on early extinguishment of debt									1,164	0	0
Other income (expense), net									(539)	(521)	(229)
Pretax income (loss)	$ (6,952)	$ (4,778)	$ 2,565	$ (2,651)	$ (22,376)	$ 3,400	$ 182	$ (1,511)	(11,816)	(20,305)	32,531
(Provision) benefit for income taxes									3,815	6,075	(15,390)
Net income (loss)									(8,001)	(14,230)	17,141
Net (income) loss attributable to non-controlling interest									(36)	14	11
Net income (loss) attributable to The New Home Company Inc.	(2,998)	(4,624)	1,572	(1,987)	(16,150)	2,459	115	(640)	(8,037)	(14,216)	17,152
Consolidation, Eliminations [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Gross Margin:
Gross margin									0	0	0
Selling and marketing expenses									0	0	0
General and administrative expenses									0	0	0
Equity in net income (loss) of unconsolidated joint ventures									0	0	0
Equity in net loss of subsidiaries									7,963	17,372	(21,773)
Gain on early extinguishment of debt									0
Other income (expense), net									0	0	0
Pretax income (loss)									7,963	17,372	(21,773)
(Provision) benefit for income taxes									0	0	0
Net income (loss)									7,963	17,372	(21,773)
Net (income) loss attributable to non-controlling interest									0	0	0
Net income (loss) attributable to The New Home Company Inc.									7,963	17,372	(21,773)
Parent Company [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Gross Margin:
Gross margin									0	0	0
Selling and marketing expenses									0	0	0
General and administrative expenses									(387)	4,330	(2,403)
Equity in net income (loss) of unconsolidated joint ventures									0	0	0
Equity in net loss of subsidiaries									(7,963)	(17,372)	21,773
Gain on early extinguishment of debt									1,164
Other income (expense), net									(286)	(66)	107
Pretax income (loss)									(7,472)	(13,108)	19,477
(Provision) benefit for income taxes									(565)	(1,108)	(2,325)
Net income (loss)									(8,037)	(14,216)	17,152
Net (income) loss attributable to non-controlling interest									0	0	0
Net income (loss) attributable to The New Home Company Inc.									(8,037)	(14,216)	17,152
Guarantor Subsidiaries [Member]
Revenues:
Revenue									669,349	667,566	751,166
Cost of Sales:
Cost of Sales									616,311	605,644	660,208
Gross Margin:
Gross margin									53,038	61,922	90,958
Selling and marketing expenses									(36,357)	(36,065)	(32,702)
General and administrative expenses									(25,333)	(30,293)	(23,927)
Equity in net income (loss) of unconsolidated joint ventures									(3,503)	(19,653)	866
Equity in net loss of subsidiaries									0	0	0
Gain on early extinguishment of debt									0
Other income (expense), net									(253)	(455)	(336)
Pretax income (loss)									(12,408)	(24,544)	34,859
(Provision) benefit for income taxes									4,380	7,183	(13,065)
Net income (loss)									(8,028)	(17,361)	21,794
Net (income) loss attributable to non-controlling interest									0	0	0
Net income (loss) attributable to The New Home Company Inc.									(8,028)	(17,361)	21,794
Non-Guarantor Subsidiaries [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									(104)	22	32
Gross Margin:
Gross margin									104	(22)	(32)
Selling and marketing expenses									0	0	0
General and administrative expenses									(3)	(3)	0
Equity in net income (loss) of unconsolidated joint ventures									0	0	0
Equity in net loss of subsidiaries									0	0	0
Gain on early extinguishment of debt									0
Other income (expense), net									0	0	0
Pretax income (loss)									101	(25)	(32)
(Provision) benefit for income taxes									0	0	0
Net income (loss)									101	(25)	(32)
Net (income) loss attributable to non-controlling interest									(36)	14	11
Net income (loss) attributable to The New Home Company Inc.									65	(11)	(21)
Home Building [Member]
Revenues:
Revenue	173,921	118,781	140,464	99,186	187,258	119,874	117,460	79,437	532,352	504,029	560,842
Cost of Sales:
Cost of Sales	153,700	105,763	123,525	86,569	162,034	102,124	102,678	69,694	469,557	436,530	473,213
Cost of sales, impairments	6,600	1,700	0	0	10,000	0	0	0	8,300	10,000	2,200
Gross Margin:
Gross margin	13,621	11,318	16,939	12,617	15,224	17,750	14,782	9,743	54,495	57,499	85,429
Pretax income (loss)									(13,868)	(24,706)	27,034
Home Building [Member] | Consolidation, Eliminations [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Cost of sales, impairments									0	0	0
Gross Margin:
Gross margin									0	0	0
Home Building [Member] | Parent Company [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Cost of sales, impairments									0	0	0
Gross Margin:
Gross margin									0	0	0
Home Building [Member] | Guarantor Subsidiaries [Member]
Revenues:
Revenue									532,352	504,029	560,842
Cost of Sales:
Cost of Sales									469,661	436,508	473,181
Cost of sales, impairments									8,300	10,000	2,200
Gross Margin:
Gross margin									54,391	57,521	85,461
Home Building [Member] | Non-Guarantor Subsidiaries [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									(104)	22	32
Cost of sales, impairments									0	0	0
Gross Margin:
Gross margin									104	(22)	(32)
Land [Member]
Revenues:
Revenue	17,091	24,573	0	0					41,664	0	0
Cost of Sales:
Cost of Sales	17,091	26,078	0	0					43,169	0	0
Cost of sales, impairments	0	1,900	0	0					1,900	0	0
Gross Margin:
Gross margin	0	(3,405)	0	0					(3,405)	0	0
Land [Member] | Consolidation, Eliminations [Member]
Revenues:
Revenue									0
Cost of Sales:
Cost of Sales									0
Cost of sales, impairments									0
Gross Margin:
Gross margin									0
Land [Member] | Parent Company [Member]
Revenues:
Revenue									0
Cost of Sales:
Cost of Sales									0
Cost of sales, impairments									0
Gross Margin:
Gross margin									0
Land [Member] | Guarantor Subsidiaries [Member]
Revenues:
Revenue									41,664
Cost of Sales:
Cost of Sales									43,169
Cost of sales, impairments									1,900
Gross Margin:
Gross margin									(3,405)
Land [Member] | Non-Guarantor Subsidiaries [Member]
Revenues:
Revenue									0
Cost of Sales:
Cost of Sales									0
Cost of sales, impairments									0
Gross Margin:
Gross margin									0
Construction [Member]
Revenues:
Revenue	31,124	22,262	22,285	19,662	42,408	39,240	38,095	43,794	95,333	163,537	190,324
Cost of Sales:
Cost of Sales	30,628	21,615	21,770	19,268	41,275	38,124	37,038	42,699	93,281	159,136	184,827
Gross Margin:
Gross margin	$ 496	$ 647	$ 515	$ 394	$ 1,133	$ 1,116	$ 1,057	$ 1,095	2,052	4,401	5,497
Pretax income (loss)									2,052	4,401	5,497
Construction [Member] | Consolidation, Eliminations [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Gross Margin:
Gross margin									0	0	0
Construction [Member] | Parent Company [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Gross Margin:
Gross margin									0	0	0
Construction [Member] | Guarantor Subsidiaries [Member]
Revenues:
Revenue									95,333	163,537	190,324
Cost of Sales:
Cost of Sales									93,281	159,136	184,827
Gross Margin:
Gross margin									2,052	4,401	5,497
Construction [Member] | Non-Guarantor Subsidiaries [Member]
Revenues:
Revenue									0	0	0
Cost of Sales:
Cost of Sales									0	0	0
Gross Margin:
Gross margin									$ 0	$ 0	$ 0