Note 8 - Inventories (Details Textual) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Inventory Write-down	$ 10,002	$ 11,098	$ 200	$ 550	$ 620	$ 4,540		$ 4,850	$ 3,873	$ 4,700	$ 1,600		$ 21,850	$ 10,010	$ 10,173
Reportable Segment, West [Member]
Inventory Write-down													$ 19,100	$ 6,000	$ 1,400
Number of Projects or Properties With Inventory Impairments During Period													7	4	1
Reportable Segment, East [Member]
Inventory Write-down													$ 1,400	$ 3,200	$ 7,600
Number of Projects or Properties With Inventory Impairments During Period													5	5	5
Reportable Segment, Mountain [Member]
Inventory Write-down													$ 1,400	$ 800	$ 1,200
Number of Projects or Properties With Inventory Impairments During Period													3	1	1