Long-Term Indebtedness (Schedule of Long-term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Unamortized deferred financing fees	$ (12,469)	$ (1,291)
Long-term debt	1,007,704	738,249
Less current portion	(65,880)	(17,831)
Long-term debt, excluding current maturities	941,824	720,418
Convertible Notes
Debt Instrument [Line Items]
Long-term debt, gross	460,000	0
Term Loan
Debt Instrument [Line Items]
Long-term debt, gross	277,500	285,000
Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross	224,482	394,888
Shelf Loan
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Other
Debt Instrument [Line Items]
Long-term debt, gross	$ 8,191	$ 9,652

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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