STOCK PLANS (Summary of Restricted Stock Awards) (Details) (Restricted stock awards, USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Restricted stock awards
Shares
Balance at beginning of year (in shares)	379,233		523,730		435,770
Shares granted (in shares)	20,099		22,779		112,864
Shares vested (in shares)	(62,524)	[1]	(159,842)	[1]	(24,904)	[1]
Shares forfeited (in shares)	0		(7,434)		0
Balance at end of year (in shares)	336,808		379,233		523,730
Weighted Average Grant Date Fair Value
Balance at beginning of year, weighted average grant date fair value (in dollars per share)	$ 28.06		$ 27.36		$ 26.61
Shares granted, weighted average grant date fair value (in dollars per share)	$ 47.81		$ 35.55		$ 31.05
Shares vested, weighted average grant date fair value (in dollars per share)	$ 32.10	[1]	$ 26.97	[1]	$ 31.07	[1]
Shares forfeited, weighted average grant date fair value (in dollars per share)	$ 0.00		$ 24.67		$ 0.00
Balance at end of year, weighted average grant date fair value (in dollars per share)	$ 28.49		$ 28.06		$ 27.36

[1] Includes shares vested but not exercisable