CAPITAL STOCK (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Common stock and treasury stock and the share activity
Authorized common stock (in shares)	199,000,000
Balance at the beginning of the year (in shares)	66,000,000
Common stock repurchased and retired	(512,000)	(1,700,000)
Balance at the end of the year (in shares)	66,700,000	66,000,000
Cash dividends paid on the common stock	$ 79,944	$ 76,659	$ 71,247
Common Stock Par Value
Common stock and treasury stock and the share activity
Balance at the beginning of the year (in shares)	66,012,843	66,685,378
Restricted stock vestings (in shares)	67,708	30,228
Common stock repurchased and retired	(511,997)	(1,726,678)
Balance at the end of the year (in shares)	66,742,490	66,012,843	66,685,378
Common Stock Par Value | Stock Awards Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)	1,173,936	1,001,748
Common Stock Par Value | Director Stock Option Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)		22,167
Treasury Stock
Common stock and treasury stock and the share activity
Balance at the beginning of the year (in shares)	3,865,863	4,168,489
Common stock repurchased (in shares)	1,411,017
Balance at the end of the year (in shares)	4,881,889	3,865,863	4,168,489
Treasury Stock | Stock Awards Plans
Common stock and treasury stock and the share activity
Stock option exercises (in shares)	(394,991)	(302,626)