Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total debt	$ 285,386	$ 443,981
Less current maturities	15,066	18,840
Total long-term debt	270,320	425,141
Term debt
Debt Instrument [Line Items]
Total debt	280,233	298,717
Finance lease liability
Debt Instrument [Line Items]
Total debt	153
Capital lease obligations
Debt Instrument [Line Items]
Total debt		264
Line of Credit | Bank revolving credit facility
Debt Instrument [Line Items]
Total debt	$ 5,000	$ 145,000