SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Weighted-Average Common Shares Outstanding Assuming Dilution) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Weighted-average common shares outstanding	132,578	132,300	132,393
Dilutive effect of Stock-Only Stock Appreciation Rights	307	611	963
Dilutive effect of Other stock compensation plans	360	474	570
Weighted-average common shares outstanding, assuming dilution	133,245	133,385	133,926