Note 12 - Related Party Transactions (Details Textual) - USD ($)	2 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended	48 Months Ended
	May 31, 2020	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Jun. 26, 2019	Apr. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Due from Affiliates		$ 108,000		$ 108,000	$ 238,000
Equity Method Investments		29,237,000		29,237,000	30,217,000
Revenue from Contract with Customer, Including Assessed Tax		132,033,000	$ 118,848,000
Cost of Goods and Services Sold, Total		120,366,000	105,837,000
Bedford 2 [Member]
Equity Method Investment, Other than Temporary Impairment		2,300,000
Interest Income on Note to Joint Venture [Member] | Encore McKinley [Member]
Debt Instrument, Interest Rate, Stated Percentage										10.00%
Bedford 2 [Member] | Subsequent Event [Member]
Sale of Business, Expected Price for Sale of Interest							$ 5,100,000
Corporate Joint Venture [Member] | Construction-related Costs [Member]
Related Party Transaction, Expenses from Transactions with Related Party		1,200,000	1,700,000
Due from Affiliates		100,000		100,000	200,000
Corporate Joint Venture [Member] | Management Fees [Member]
Due from Affiliates		0		$ 0	0
Due from Affiliates		$ 400,000	500,000
Related Party [Member]
Common Stock Beneficial Ownership Percentage, Significant Amount Threshold		10.00%		10.00%
TNHC Merdian Investors LLC, and TNHC Russel Ranch LLC [Member]
Equity Method Investments		$ 15,600,000		$ 15,600,000	13,700,000
IHP [Member] | LLC Agreement of Russell Ranch [Member]
Joint Venture Agreement, Additional Required Capital Agreed to Fund									$ 26,000,000
Joint Venture Agreement, Additional Required Capital Agreed to Fund, Percentage Funded by Related Party									50.00%
Joint Venture Agreement, Additional Required Capital Agreed to Fund, Percentage Funded by Entity									50.00%
TL Fab LP [Member] | Trade Payment [Member] | Unconsolidated Joint Ventures [Member]
Related Party Transaction, Amounts of Transaction		0	33,000
Accounts Payable, Related Parties		0		0	0
TNHC-HW Cannery LLC [Member]
Due from Affiliates		15,000		15,000	15,000
Deferred Profit From Lot Transactions		200,000		200,000	200,000
Related Party Transaction, Profit Participation Due		0	0
Consultant Davis [Member]
Due from Affiliates		0		0	0
Consultant Davis [Member] | Fee Building Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax			500,000
Cost of Goods and Services Sold, Total			500,000
Consultant Davis [Member] | General Contractor [Member]
Revenue from Contract with Customer, Including Assessed Tax			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
Consultant Stelmar [Member] | Monthly Consulting Fee [Member]
Related Party Transaction, Amounts of Transaction		0	$ 18,000
Accounts Payable, Related Parties		0		0	0
Consultant Redwitz [Member] | Forecast [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
10% Common Stock Affiliate [Member] | Northern CA Phased Takedown [Member]
Purchase Options, Land											$ 16,100,000
Master Marketing Fees		400,000
10% Common Stock Affiliate [Member] | Northern CA Rolling Option [Member]
Related Party Transaction, Profit Participation Due		200,000
Estimated Purchase Price					$ 56,300,000
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
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		3,800,000
Deposits Assets		300,000		300,000
Bedford [Member]
Purchase Options, Land		10,000,000.0		10,000,000.0
Deposits Assets		1,500,000		1,500,000
Board Affiliate [Member] | Bedford [Member]
Purchase Options, Land								$ 9,300,000
Master Marketing Fees		100,000
Board Affiliate [Member] | Bedford 2 [Member]
Purchase Options, Land		10,500,000		10,500,000
Master Marketing Fees		200,000
Deposits Assets		$ 1,400,000		$ 1,400,000
Percentage of Optioned Lots Taken Down		92.00%	42.00%	92.00%
Deposit Assets Outstanding		$ 0		$ 0