Note 12 - Related Party Transactions (Details Textual) - USD ($)	2 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended		48 Months Ended
	May 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 26, 2019	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Due from Affiliates			$ 140,000		$ 140,000		$ 140,000	$ 238,000
Equity Method Investments			12,931,000		12,931,000		12,931,000	30,217,000
Revenue from Contract with Customer, Including Assessed Tax			98,960,000	$ 162,749,000	230,993,000	$ 281,597,000
Cost of Goods and Services Sold, Total			106,211,000	145,295,000	226,577,000	251,132,000
Bedford 2 [Member]
Equity Method Investment, Other than Temporary Impairment					$ 2,300,000
Joint Venture, Option Rights, Percentage					30.00%
Bedford 2 [Member] | Forecast [Member]
Proceeds from Sale of Equity Method Investments		$ 5,100,000
Unconsolidated Joint Ventures [Member]
Equity Method Investment, Other than Temporary Impairment			20,000,000.0	0	$ 22,300,000	0
Unconsolidated Joint Ventures [Member] | Forecast [Member]
Proceeds from Sale of Equity Method Investments		$ 5,100,000
Interest Income on Note to Joint Venture [Member] | Encore McKinley [Member]
Debt Instrument, Interest Rate, Stated Percentage											10.00%
Corporate Joint Venture [Member] | Construction-related Costs [Member]
Related Party Transaction, Expenses from Transactions with Related Party			1,000,000.0	1,500,000	2,200,000	3,200,000
Due from Affiliates			100,000		100,000		100,000	200,000
Corporate Joint Venture [Member] | Management Fees [Member]
Due from Affiliates			4,000		4,000		$ 4,000	0
Revenue from Related Parties			$ 200,000	600,000	$ 600,000	1,200,000
Related Party [Member]
Common Stock Beneficial Ownership Percentage, Significant Amount Threshold			10.00%		10.00%		10.00%
TNHC Merdian Investors LLC, and TNHC Russel Ranch LLC [Member]
Equity Method Investments			$ 300,000		$ 300,000		$ 300,000	13,700,000
IHP [Member] | LLC Agreement of Russell Ranch [Member]
Joint Venture Agreement, Additional Required Capital Agreed to Fund				$ 26,000,000		$ 26,000,000
Joint Venture Agreement, Additional Required Capital Agreed to Fund, Percentage Funded by Related Party				50.00%		50.00%
Joint Venture Agreement, Additional Required Capital Agreed to Fund, Percentage Funded by Entity				50.00%		50.00%
TL Fab LP [Member] | Trade Payment [Member] | Unconsolidated Joint Ventures [Member]
Related Party Transaction, Amounts of Transaction			7,000	$ 22,000	7,000	$ 55,000
Accounts Payable, Related Parties			0		0		0	0
TNHC-HW Cannery LLC [Member]
Due from Affiliates			0		0		0	15,000
Deferred Profit From Lot Transactions			200,000		200,000		200,000	200,000
Land Owner Fees Reimbursed			15,000	0	15,000	0
Consultant Davis [Member]
Due from Affiliates			0		0		0	0
Consultant Davis [Member] | Fee Building Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax				10,000		500,000
Cost of Goods and Services Sold, Total				13,000		500,000
Consultant Davis [Member] | General Contractor [Member]
Revenue from Contract with Customer, Including Assessed Tax				0		15,000
Consultant Davis [Member] | Monthly Consulting Fee [Member]
Related Party Transaction, Amounts of Transaction							1,000		$ 5,000
Accounts Payable, Related Parties			0		0		0
Consultant Stelmar [Member] | Monthly Consulting Fee [Member]
Related Party Transaction, Amounts of Transaction			0	$ 18,000	0	$ 36,000
Consultant Redwitz [Member]
Related Party Transaction, Amounts of Transaction	$ 5,000
Consultant Redwitz [Member] | Monthly Consulting Fee [Member]
Related Party Transaction, Amounts of Transaction					10,000
Accounts Payable, Related Parties			0		0		0
10% Common Stock Affiliate [Member] | Northern CA Phased Takedown [Member]
Purchase Options, Land												$ 16,100,000
Master Marketing Fees					500,000
10% Common Stock Affiliate [Member] | Northern CA Rolling Option [Member]
Land Owner Fees Reimbursed					200,000
Estimated Purchase Price								$ 56,300,000
Percentage of Optioned Lots Taken Down				10.00%		10.00%
Percentage of Lots Agreed to Be Purchased by Unrelated Third Party								67.00%
Number of Lots Remaining to Purchase From Affiliate								0
Deposit Assets, Total			$ 0		0		$ 0
Option Payment					3,000,000.0
Amounts Paid for Purchase of Lots					$ 18,000,000.0
10% Common Stock Affiliate [Member] | Arizona Master Plan [Member]
Purchase Options, Land											$ 3,800,000
Percentage of Optioned Lots Taken Down			11.00%		11.00%		11.00%
Deposits Assets			$ 300,000		$ 300,000		$ 300,000
Bedford [Member]
Purchase Options, Land			10,000,000.0		10,000,000.0		10,000,000.0
Deposits Assets			1,500,000		1,500,000		1,500,000
Board Affiliate [Member] | Bedford [Member]
Purchase Options, Land										$ 9,300,000
Master Marketing Fees					100,000
Percentage of Optioned Lots Taken Down				12.00%		12.00%
Board Affiliate [Member] | Bedford 2 [Member]
Purchase Options, Land			$ 10,500,000		10,500,000		$ 10,500,000
Master Marketing Fees					$ 200,000
Percentage of Optioned Lots Taken Down			92.00%	42.00%	92.00%	42.00%	92.00%
Deposits Assets			$ 1,400,000		$ 1,400,000		$ 1,400,000
Deposit Assets Outstanding			$ 0		$ 0		$ 0