Note 7 - Inventories (Details Textual) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Inventory Write-down	$ 3,873	$ 4,700	$ 1,600		$ 5,200	$ 3,225		$ 350	$ 910		$ 850		$ 10,173	$ 8,775	$ 1,760
Number of Projects or Properties With Inventory Impairments During Period															4
Maryland Division [Member]
Inventory Write-down															$ 1,000
Number of Projects or Properties With Inventory Impairments During Period															3
Reportable Segment, East [Member]
Inventory Write-down													$ 7,600
Number of Projects or Properties With Inventory Impairments During Period													5
Reportable Segment, West [Member]
Inventory Write-down													$ 1,400
Number of Projects or Properties With Inventory Impairments During Period													1
Reportable Segment, Mountain [Member]
Inventory Write-down													$ 1,200
Number of Projects or Properties With Inventory Impairments During Period													1
Land Held for Sale [Member]
Inventory, Real Estate, Land and Land Development Costs					$ 1,700									1,700
Inventory Write-down														$ 1,200
Number of Projects or Properties With Inventory Impairments During Period														2
Land Held for Sale [Member] | Reportable Segment, West [Member]
Number of Projects or Properties With Inventory Impairments During Period														1
Land Held for Sale [Member] | Reportable Segment, Mountain [Member]
Number of Projects or Properties With Inventory Impairments During Period														1
Other Than Land Held for Sale [Member]
Inventory Write-down														$ 8,800
Other Than Land Held for Sale [Member] | Maryland Division [Member]
Inventory Write-down														$ 3,300
Number of Projects or Properties With Inventory Impairments During Period														4
Other Than Land Held for Sale [Member] | Virginia Division [Member]
Inventory Write-down														$ 5,200
Number of Projects or Properties With Inventory Impairments During Period														3
Other Than Land Held for Sale [Member] | Reportable Segment, East [Member] | Majority from the East [Member]
Number of Projects or Properties With Inventory Impairments During Period														9