Long-Term Indebtedness (Schedule of Long-term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Unamortized deferred financing fees	$ (328)	$ (361)
Long-term debt	245,923	294,124
Less current portion	(613)	(596)
Long-term debt, excluding current maturities	245,310	293,528
Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross	190,600	240,060
Shelf Loan
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Other
Debt Instrument [Line Items]
Long-term debt, gross	$ 5,651	$ 4,425

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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