Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 26, 2018	Mar. 16, 2018	Mar. 27, 2014	Jun. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				100,000,000	100,000,000
Common stock, par value (in dollars per share)				$ 0.01	$ 0.01
Common stock, shares issued (in shares)				50,719,884	50,598,901
Common stock, shares outstanding (in shares)				50,719,884	50,598,901
Preferred stock, shares authorized (in shares)				5,000,000	5,000,000
Preferred stock, par value (in dollars per share)				$ 0.01	$ 0.01
Preferred stock, shares issued (in shares)				0	0
Preferred stock, shares outstanding (in shares)				0	0
GHO Homes
Class of Stock [Line Items]
Ownership percentage by noncontrolling owners	20.00%
Period of financial results prior to exercise of option used to determine exercise price	3 years
Fair value of estimated payment to repurchase shares	$ 6.3
Option to repurchase interest from partner if put option not exercised by controlled builder, percent of interest	20.00%
Common Stock | Challenger Homes
Class of Stock [Line Items]
Common stock issued in connection with the investment in the Challenger Subsidiary (in shares)		20,000
Preferred Share Purchase Right
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)			$ 0.01
Preferred share purchase right dividend (in shares)			1
Exercise price of rights (in dollars per share)			$ 30.00
Series B Junior Participating Preferred Stock
Class of Stock [Line Items]
Number of securities called by each right (in shares)			0.001
Preferred Stock
Class of Stock [Line Items]
Number of securities called by each right (in shares)			0.001