Debt (Schedule of Debt) (Details) - SunTrust Bank [Member] - USD ($)		3 Months Ended
	Jan. 19, 2010	Mar. 31, 2018	Dec. 31, 2018	May 04, 2017	May 03, 2017
Debt Instrument [Line Items]
Credit facility, term	4 years
Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Sun Trust Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 15,000,000.0			$ 35,000,000.0	$ 20,000,000.0
Scenario, Forecast [Member] | Subsequent Event [Member] | Sun Trust Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 30,000,000.0