STOCK COMPENSATION PLANS (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock purchase plan
Compensation expense	$ 22,102,000	$ 16,502,000	$ 13,883,000
Stock Purchase Plan
Stock purchase plan
Purchase price of shares in terms compared to market price per share (as a percent)	90.00%
Annual purchase limitation per employee	$ 22,500
Compensation expense	$ 0
Common stock, shares authorized (in shares)	2,000,000
Shares sold to employees (in shares)	67,198	55,485
Value of shares sold to employees under purchase plan	$ 2,100,000	$ 2,000,000
Shares available (in shares)	572,030