STOCK PLANS AND SHARE BASED COMPENSATION (Performance-based Awards and Restricted Stock Units) (Details) (USD $)	1 Months Ended	3 Months Ended
	Jan. 31, 2012	Mar. 31, 2012 years	Mar. 31, 2011
Performance-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance-based awards shares released as percentage of target number, minimum		0.00%
Number of performance-based awards shares released as percentage of target number, maximum		200.00%
Reduction in number of shares available for issuance under the 2007 Plan per award granted		2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, shares, at January 1, 2012	0	0
Outstanding, weighted-average grant date fair value per share, at January 1, 2012	$ 0.00	$ 0.00
Granted, shares		96,000
Granted, weighted-average grant date fair value per share		$ 37.28	$ 36.90
Vested, shares		0
Vested, weighted-average grant date fair value per share		$ 0.00
Forfeited or expired, shares	(93,000)	0
Forfeited or expired, weighted-average grant date fair value per share		$ 0.00
Outstanding, shares, at March 31, 2012		96,000
Outstanding, weighted-average grant date fair value per share, at March 31, 2012		$ 37.28
Outstanding, weighted-average remaining contractual term (in years)		0.75
Outstanding, aggregate intrinsic value		$ 3,556,000
Outstanding and expected to vest, shares		92,000
Vested and expected to vest, weighted-average remaining contractual term (in years)		0.75
Vested and expected to vest, aggregate intrinsic value		3,409,000
Grant date fair value of awards released			3,000,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in number of shares available for issuance under the 2007 Plan per award granted		2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, shares, at January 1, 2012	458,000	458,000
Outstanding, weighted-average grant date fair value per share, at January 1, 2012	$ 36.08	$ 36.08
Granted, shares		3,000
Granted, weighted-average grant date fair value per share		$ 35.12	$ 38.66
Vested, shares		(5,000)
Vested, weighted-average grant date fair value per share		$ 37.23
Forfeited or expired, shares		(6,000)
Forfeited or expired, weighted-average grant date fair value per share		$ 37.09
Outstanding, shares, at March 31, 2012		450,000
Outstanding, weighted-average grant date fair value per share, at March 31, 2012		$ 36.04
Outstanding, weighted-average remaining contractual term (in years)		1.38
Outstanding, aggregate intrinsic value		16,708,000
Outstanding and expected to vest, shares		420,000
Vested and expected to vest, weighted-average remaining contractual term (in years)		1.37
Vested and expected to vest, aggregate intrinsic value		15,596,000
Grant date fair value of awards released		$ 200,000	$ 100,000