STOCK-BASED COMPENSATION (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Stock Appreciation Rights (SARs) [Member]	Jun. 30, 2011 Stock Appreciation Rights (SARs) [Member]	Sep. 30, 2012 Stock Appreciation Rights (SARs) [Member]	Sep. 30, 2011 Stock Appreciation Rights (SARs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2011 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Performance-based Awards [Member]	Dec. 31, 2011 Performance-based Awards [Member]	Sep. 30, 2012 Performance-based Awards - Peer Group Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Fair Value (in dollars per share)					$ 24.33	$ 16.42	$ 27.89	$ 26.47	$ 62.49	$ 64.27	$ 60.05		$ 75.72
Performance-based awards outstanding (in shares)									191,026	191,026		203,291	46,500	0	23,250
Stock-based compensation expense	$ 3,200,000	$ 2,900,000	$ 11,722,000	$ 12,360,000
Total unrecognized compensation cost	21,400,000		21,400,000
Compensation cost expected to be recognized over the remainder of 2012			3,400,000
Compensation cost expected to be recognized in 2013			11,400,000
Compensation cost expected to be recognized in 2014			5,900,000
Compensation cost expected to be recognized in 2015			700,000
Total intrinsic value of awards exercised			22,400,000	12,000,000
Cash received from exercise of options			200,000
Tax benefit associated with exercise of awards			$ 5,400,000	$ 3,500,000