Long-Term Debt (Credit Facility) (Narrative) (Details) - USD ($)				3 Months Ended		6 Months Ended
	May 18, 2018	Apr. 25, 2018	Apr. 24, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Mar. 09, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Deferred financing fees				$ 1,310,000		$ 1,310,000		$ 749,000
Amortization of deferred financing costs						100,000
Proceeds under New Markets Tax Credit financing						$ 2,835,000
New Markets Tax Credit (NMTC) Program [Member]
Line of Credit Facility [Line Items]
Deferred financing fees							$ 700,000
PNC Bank [Member]
Line of Credit Facility [Line Items]
Minimum fixed charge coverage ratio				110.00%		110.00%
Term Loan [Member] | Letter Agreement [Member]
Line of Credit Facility [Line Items]
Proceeds from equity offering	$ 1,300,000
Credit facility, commitment allocation, percentage	50.00%
Revolving Credit Facility [Member] | Letter Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment allocation, percentage	50.00%
Revolving Credit Facility [Member] | PNC Bank [Member]
Line of Credit Facility [Line Items]
Maximum secured borrowing capacity			$ 73,000,000	$ 65,000,000		$ 65,000,000
Increase in maximum aggregate principal amount of borrowings			$ 8,000,000
Debt Instrument, Maturity Date, Description						The Facilities, which expire upon the earlier of (i) January 21, 2021 or (ii) the date that is 90 days prior to the scheduled maturity date of the notes
Commitment fee on the daily unused portion of the Revolver						0.25%
Deferred financing fees				600,000		$ 600,000
Revolving Credit Facility [Member] | PNC Bank [Member] | Restricted Cash
Line of Credit Facility [Line Items]
Proceeds under New Markets Tax Credit financing				$ 2,200,000
Revolving Credit Facility [Member] | PNC Bank [Member] | New Markets Tax Credit (NMTC) Program [Member]
Line of Credit Facility [Line Items]
Increase in maximum aggregate principal amount of borrowings					$ 6,700,000
Revolving Credit Facility [Member] | PNC Bank [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, effective interest rate				3.99%		3.99%
Revolving Credit Facility [Member] | PNC Bank [Member] | Letter Agreement [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Proceeds from equity offering	$ 30,000,000
Revolving Credit Facility [Member] | PNC Bank [Member] | Letter Agreement [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Proceeds from credit facility in excess	$ 30,000,000
Revolving Credit Facility [Member] | PNC Bank [Member] | Request to Increase Borrowing Prior to January 21, 2020 [Member]
Line of Credit Facility [Line Items]
Increase in maximum aggregate principal amount of borrowings		$ 17,000,000
Letter of Credit [Member] | PNC Bank [Member]
Line of Credit Facility [Line Items]
Maximum secured borrowing capacity				$ 10,000,000		$ 10,000,000
Term Loan [Member] | PNC Bank [Member]
Line of Credit Facility [Line Items]
Maximum secured borrowing capacity				$ 30,000,000		$ 30,000,000
Debt Instrument, Frequency of Periodic Payment						quarterly
Quarterly term loan payments						$ 1,100,000
Term Loan [Member] | PNC Bank [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, effective interest rate				4.49%		4.49%
Swing Loan Credit Facility [Member] | PNC Bank [Member]
Line of Credit Facility [Line Items]
Maximum secured borrowing capacity				$ 6,500,000		$ 6,500,000