STOCKHOLDERS' EQUITY (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Jul. 31, 2012
STOCKHOLDERS' EQUITY
Cash dividend paid	$ 13,146	$ 11,726
Cash dividend per share (in dollars per share)	$ 0.09	$ 0.08
Number of shares repurchased (in shares)		68,000
Par value of common stock (in dollars per share)	$ 1		$ 1
Weighted average stock price of shares repurchased (in dollars per share)		$ 19.58
Number of shares of common stock authorized for repurchase (in shares)				5,000,000
Repurchase of common stock from employees	4,500,000	3,400,000
Additional shares that may be purchased under share repurchase program (in shares)	5,300,000
Common stock reserved for issuance upon exercise of stock options (in shares)	4,000,000