LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Total Outstanding Debt (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Finance leases	$ 0	$ 35,000
Total	270,438,000	272,641,000
Less portion due within one year	(9,789,000)	(9,928,000)
Total long-term debt, net of debt issuance costs	$ 260,649,000	262,713,000
Revolver Loan Due August 31, 2023 | Revolving Credit Facility
Debt Instrument [Line Items]
Effective Rate (as a percent)	4.25%
Long-term debt, gross	$ 134,500,000	126,500,000
Term Loan Due August 31, 2023
Debt Instrument [Line Items]
Effective Rate (as a percent)	4.25%
Long-term debt, gross	$ 135,938,000	$ 146,106,000
Finance Leases
Debt Instrument [Line Items]
Effective Rate (as a percent)	1.65%