STOCK COMPENSATION PLANS (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock purchase plan
Compensation expense recognized	$ 16,502,000	$ 13,883,000	$ 13,531,000
Shares available under the Purchase Plan	3,000,000
Stock Purchase Plan
Stock purchase plan
Purchase price of shares in terms compared to market price per share (as a percent)	90.00%
Value of shares sold to employees under purchase plan	$ 22,500.0
Compensation expense recognized	$ 0
Common stock, shares authorized (in shares)	2,000,000
Shares sold to employees under purchase plan (in shares)	55,485	58,587
Value of shares sold to employees under purchase plan	$ 2,000,000	$ 1,900,000
Shares available under the Purchase Plan	639,228