STOCK PLANS (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Number of Options
Exercised (in shares)	(878,658)	(790,596)
Stock options
Number of Options
Outstanding at beginning of year (in shares)	2,505,101	3,407,761	2,758,979
Granted (in shares)			935,000
Exercised (in shares)	(878,658)	(790,596)
Forfeited (in shares)	(86,250)	(112,064)	(286,218)
Outstanding at end of year (in shares)	1,540,193	2,505,101	3,407,761
Exercisable at end of year (in shares)	1,062,193	1,683,101	2,245,511
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 14.22	$ 13.75	$ 15.20
Granted (in dollars per share)			$ 10.24
Exercised (in dollars per share)	$ 14.97	$ 12.20
Forfeited (in dollars per share)	$ 13.54	$ 14.20	$ 16.25
Outstanding at end of year (in dollars per share)	$ 13.83	$ 14.22	$ 13.75
Exercisable at end of year (in dollars per share)	$ 15.28	$ 15.67	$ 14.86
Weighted Average Remaining Contractual Term
Outstanding at end of year (in years)	$ 4.35	$ 4.47	$ 4.38
Exercisable at end of year (in years)	$ 4.06	$ 3.72	$ 3.02
Aggregate Intrinsic Value
Exercised	$ 4,731,919	$ 905,051
Forfeited	565,800	35,192
Outstanding at end of year	3,631,381	7,742,565
Exercisable at end of year	$ 1,597,081	$ 2,961,443
Restricted stock
Number of Restricted Shares Granted
Outstanding at beginning of year (in shares)	878,520
Granted (in shares)	762,004
Forfeited (in shares)	(30,000)
Vested (in shares)	(223,972)
Outstanding at end of year (in shares)	1,386,552
Weighted Average Fair Value
Outstanding at beginning of year (in dollars per share)	$ 14.94
Granted (in dollars per share)	$ 21.42
Forfeited (in dollars per share)	$ 21.58
Vested (in dollars per share)	$ 12.92
Outstanding at end of year (in dollars per share)	$ 18.69