Note 6 - Investments in and Advances to Unconsolidated Joint Ventures - Inventory Impairments (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Total joint venture impairments	$ 70,000,000.0	$ 28,776,000	$ 0
Number of projects impaired during the year	1	1	0
Total number of projects included in unconsolidated joint ventures and reviewed for impairment during the year	10	10	10
Homebuilding Joint Ventures [Member]
Total joint venture impairments	$ 0	$ 0	$ 0
Land Development Joint Ventures [Member]
Total joint venture impairments	$ 70,000,000	$ 28,776,000	$ 0