Contractual interest rate for funds borrowed, under the debt agreement.

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Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Total long term debt	$ 568,908	$ 565,312
Less: current maturities	(23,770)	(23,355)
Long-term debt, less current maturities	545,138	541,957
Senior Notes \| 5.75% Senior Notes Due 2028
Debt Instrument [Line Items]
Total long term debt	295,919	295,770
Unamortized debt issuance costs	4,081	4,230
Notes payable interest rate			5.75%
Medium-term Notes \| Term Loan Agreement
Debt Instrument [Line Items]
Total long term debt	198,740	198,657
Unamortized debt issuance costs	1,260	1,343
Notes Payable
Debt Instrument [Line Items]
Total long term debt	$ 5,428	3,392
Notes Payable \| Minimum
Debt Instrument [Line Items]
Notes payable interest rate	1.00%
Notes Payable \| Maximum
Debt Instrument [Line Items]
Notes payable interest rate	5.00%
Notes Payable \| Vehicle and Equipment
Debt Instrument [Line Items]
Total long term debt	$ 68,821	$ 67,493
Notes Payable \| Vehicle and Equipment \| Minimum
Debt Instrument [Line Items]
Notes payable interest rate	1.90%
Notes Payable \| Vehicle and Equipment \| Maximum
Debt Instrument [Line Items]
Notes payable interest rate	4.80%