LEASE COMMITMENTS - Maturities of Lease Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Maturities of operating lease liabilities:
Year 1	$ 21,351,000
Year 2	18,278,000
Year 3	10,999,000
Year 4	7,844,000
Year 5	6,388,000
Thereafter	14,880,000
Total lease payments	79,740,000
Less imputed interest	(8,724,000)
Total operating lease liabilities	71,016,000	$ 71,854,000
Maturities of finance lease liabilities:
Year 1	5,542,000
Year 2	4,378,000
Year 3	3,509,000
Year 4	2,973,000
Year 5	2,918,000
Thereafter	18,080,000
Total lease payments	37,400,000
Less imputed interest	(7,375,000)
Total finance lease liabilities	30,025,000	$ 29,952,000
Amount of additional operating leases that have not yet commenced	100,000
Amount of additional finance leases that have not yet commenced	$ 0
Minimum
Maturities of finance lease liabilities:
Term of operating and finance leases that have not yet commenced (in years)	3 years
Maximum
Maturities of finance lease liabilities:
Term of operating and finance leases that have not yet commenced (in years)	4 years