ACCUMULATED OTHER COMPREHENSIVE INCOME LOSS ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Reclass) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Earnings before income taxes									$ 263,051	$ 396,462	$ 356,239
Provision for income taxes									(61,659)	(88,879)	(80,490)
Net earnings	$ 53,993	$ 64,620	$ 31,018	$ 51,761	$ 89,408	$ 82,510	$ 80,072	$ 55,593	201,392	307,583	$ 275,749
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax									926	939
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax									(23,057)	(9,112)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Curtailments, before Tax									(1,086)	0
Earnings before income taxes									(23,217)	(8,173)
Provision for income taxes									5,568	1,978
Net earnings									$ (17,649)	$ (6,195)