STOCK REPURCHASE PROGRAM (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011
STOCK REPURCHASE PROGRAM
Number of shares repurchased	610,000	799,000
Aggregate amount of share repurchases (in dollars)	$ 30,800	$ 40,896	$ 79,640
Remaining authorization to repurchase additional shares	2,800,000	2,800,000