Business Acquisition - (Details) $ in Thousands				3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Apr. 03, 2017 USD ($)	Jul. 01, 2015 USD ($) item	Dec. 31, 2017 USD ($)	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 ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisitions
Contingent consideration (earn-out)												$ 1,818		$ 6,000
Total revenues				$ 280,772	$ 205,739	$ 201,194	$ 155,548	$ 261,692	$ 205,427	$ 188,096	$ 124,090	843,253	$ 779,305	517,766
Net income (loss)				$ (23,545)	$ (1,477)	$ 647	$ 2,439	$ 17,058	$ 11,897	$ 117,361	$ 791	(21,936)	$ 147,107	$ 11,950
Savvy Homes
Business Acquisitions
Acquisition price		$ 42,968
Total revenues												53,200
Net income (loss)												$ (4,000)
Bonterra Builders, LLC
Business Acquisitions
Acquisition price			$ 99,759
Contingent consideration payments			5,700
Consideration held as security			$ 800
Number of primary residential lots | item			1,700
Earn-out | Savvy Homes
Business Acquisitions
Contingent consideration (earn-out)	$ 0	$ 1,818
Reversal of earn-out	$ 1,800
Earn-out | Bonterra Builders, LLC
Business Acquisitions
Contingent consideration (earn-out)			$ 6,000