Debt (Schedule of Notes Payable Outstanding) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Notes payable	$ 9,914	$ 9,926	[1]
Notes Payable | Briar Ridge Investments, LTD
Debt Instrument [Line Items]
Notes payable	9,000	9,000
Notes Payable | Graham Mortgage Corporation
Debt Instrument [Line Items]
Notes payable	$ 914	$ 926

[1] The Condensed Consolidated Balance Sheet at December 31, 2017 has been derived from the audited financial statements at that date, but does not include all of the footnotes required by U.S. generally accepted accounting principles for complete financial statements.