Significant Accounting Policies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Line Items]
Allowance for doubtful accounts		$ 0
Asset Impairment Charges		0
Earnest money deposits written-off during period	$ 700,000	200,000	$ 200,000
Deferred tax assets	16,565,000	31,265,000
Deferred income tax assets, net	16,499,000	31,211,000
Valuation allowance for deferred tax assets	(1,063,000)	(1,346,000)	(1,147,000)
Deferred tax asset related to net operating loss carryforwards	432,000	14,078,000
Selling, general and administrative expense	$ 56,830,000	$ 39,016,000	38,629,000
Minimum
Accounting Policies [Line Items]
Community life cycle		2 years
Useful lives of assets	1 year
Maximum
Accounting Policies [Line Items]
Community life cycle		6 years
Useful lives of assets	15 years
Selling, General and Administrative Expenses
Accounting Policies [Line Items]
Advertising expense		$ 1,500,000	$ 800,000	$ 700,000
Federal
Accounting Policies [Line Items]
Net operating loss carryforward		$ 2,000,000
Operating loss carryforward, expiration date	Dec. 31, 2029
State
Accounting Policies [Line Items]
Operating loss carryforward, expiration date	Dec. 31, 2023