CAPITAL STOCK (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common stock and treasury stock and the share activity
Authorized common stock (in shares)	199,000,000	199,000,000
Balance at the beginning of the year (in shares)	68,600,000
Balance at the end of the year (in shares)	69,500,000	68,600,000
Cash dividends paid on the common stock	$ 92,658	$ 90,208	$ 82,346
Common Stock Par Value
Common stock and treasury stock and the share activity
Balance at the beginning of the year (in shares)	68,608,508	67,341,316	66,742,490
Restricted stock vestings (in shares)	79,700	41,268	39,691
Common stock repurchased and retired (in shares)	0	0	(623,412)
Balance at the end of the year (in shares)	69,516,805	68,608,508	67,341,316
Common Stock Par Value | Stock Awards Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)	802,046	1,079,841	1,182,547
Common Stock Par Value | Director Stock Option Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)	26,551	146,083	0
Treasury Stock
Common stock and treasury stock and the share activity
Balance at the beginning of the year (in shares)	4,836,027	4,424,884	4,881,889
Common stock repurchased (in shares)	0	778,848	45,000
Balance at the end of the year (in shares)	4,528,051	4,836,027	4,424,884
Treasury Stock | Stock Awards Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)	307,976	367,705	502,005