Revenue Recognition (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 149,992	$ 113,706	$ 433,267	$ 317,994
Transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenues				15,815
Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	137,399	108,437	401,643	302,179
Residential Real Estate [Member] | Transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	137,399	108,437	401,643	302,179
Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	12,593	5,269	31,624	15,815
Real Estate, Other [Member] | Transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	12,593	5,269	31,624
1531 Operative Builders [Member] | Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
1531 Operative Builders [Member] | Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	12,593	5,269	31,624	15,815
Individual Counterparty [Member] | Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	137,399	108,437	401,643	302,179
Individual Counterparty [Member] | Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Central
Disaggregation of Revenue [Line Items]
Total revenues				15,013
Central | Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	59,652	52,597	198,093	149,977
Central | Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	12,363	5,269	27,054
Southeast [Domain] | Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	77,747	55,840	203,550	152,202
Southeast [Domain] | Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	230	0	4,570	802
Land development
Disaggregation of Revenue [Line Items]
Total revenues	12,363	5,269		15,815
Land development | Residential Real Estate [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Builder operations
Disaggregation of Revenue [Line Items]
Total revenues	137,629
Builder operations | Real Estate, Other [Member]
Disaggregation of Revenue [Line Items]
Total revenues	200	0	4,600
Builder operations | Land and Lots [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0		$ 0	0
Builder operations | Central
Disaggregation of Revenue [Line Items]
Total revenues	59,652	52,597		149,977
Builder operations | Southeast [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	$ 77,977	$ 55,840		$ 152,202