Long-Term Debt Long-term Debt - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 05, 2016	May 26, 2016	Apr. 29, 2016	Sep. 22, 2006
SBA Note Payable
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 20,000
Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Debt Instrument, Face Amount		$ 30,000
Interboro, LLC Promissory Note
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 8,550
BB&T Term Note Payable
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.65%
Debt Instrument, Face Amount			$ 5,200
150M Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Debt Instrument, Face Amount	$ 150,000