NET INCOME PER SHARE (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Unvested Stock Awards Outstanding and Convertible Debt Securities [Member]	Sep. 30, 2012 Unvested Stock Awards Outstanding and Convertible Debt Securities [Member]	Sep. 30, 2013 Unvested Stock Awards Outstanding and Convertible Debt Securities [Member]	Sep. 30, 2012 Unvested Stock Awards Outstanding and Convertible Debt Securities [Member]	Sep. 30, 2013 Convertible Debt [Member]	Sep. 30, 2013 Convertible Debt [Member]	Dec. 31, 2006 Convertible Debt 0.75 Percent Due September 2013 [Member]	Oct. 23, 2013 Subsequent Event [Member]
Anti-dilutive Securities Excluded From Computation Of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount					2,923,000	2,335,000	2,931,000	2,246,000	2,400,000	2,500,000
Weighted average number of basic common shares outstanding (in shares)	51,363,000	49,851,000	50,690,000	49,830,000
Weighted average dilutive stock options, restricted stock, restricted stock units and performance share units (in shares)	338,000	353,000	359,000	475,000
Assumed conversion of convertible debt (in shares)	1,283,000	981,000	1,177,000	990,000
Weighted average number of diluted common and common equivalent shares outstanding (in shares)	52,984,000	51,185,000	52,226,000	51,295,000
Debt Instrument Convertible Debt Hedge Transactions [Abstract]
Aggregate principal amount											$ 172.5
Settlement of Conversion Spread Hedges (in shares)												42,160