DEBT (Additional Information) (Detail) (USD $)							9 Months Ended		9 Months Ended		9 Months Ended					1 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Senior Credit Facility	Dec. 31, 2011 Senior Credit Facility	Sep. 30, 2012 Senior Credit Facility Option X	Sep. 30, 2012 Senior Credit Facility Option Z	Sep. 30, 2012 Senior Credit Facility Minimum	Sep. 30, 2012 Senior Credit Facility Minimum Option i	Sep. 30, 2012 Senior Credit Facility Maximum	Sep. 30, 2012 Senior Credit Facility Maximum Option i	Sep. 30, 2012 Senior Credit Facility August 2010 Amendment	Sep. 30, 2012 Senior Credit Facility June 2011 Amendment [Member]	Sep. 30, 2012 Senior Credit Facility June 2011 Amendment [Member] Maximum	May 31, 2012 Senior Credit Facility May 2012 Amendment Minimum	May 31, 2012 Senior Credit Facility May 2012 Amendment Maximum	Jun. 30, 2011 2016 Convertible Senior Notes	Sep. 30, 2012 2016 Convertible Senior Notes	Dec. 31, 2011 2016 Convertible Senior Notes	Jun. 15, 2011 2016 Convertible Senior Notes	Sep. 30, 2012 2012 Senior Convertible Notes	Jun. 11, 2007 2012 Senior Convertible Notes
Debt Instrument [Line Items]
Senior credit facility size increased to												$ 450,000,000	$ 600,000,000
Reallocated term loan												150,000,000
Additional commitments												200,000,000
Line of credit facility, expiration date											Aug. 10, 2015	Jun. 08, 2016
Maximum consolidated total leverage ratio (net debt to consolidated EBITDA)														1	3.75
Interest rates available to the Company at its option					0.50%	1.00%		1.00%		1.75%
Cash balance threshold above which excess amount is not subject to any restriction of use or investment			40,000,000
Line of credit, commitment fee percentage							0.15%		0.30%
Line of credit facility outstanding			321,900,000	179,700,000
Weighted average interest rate on debt			1.80%	2.00%
Available borrowings under senior secured revolving credit facility			278,100,000
Fair value of outstanding borrowings			299,100,000														227,100,000
Principal amount outstanding																	230,000,000	230,000,000	230,000,000		165,000,000
Interest rate on debt																			1.625%
Portion of the debt proceeds that was classified as equity at the time of the offering																			43,200,000
Effective interest rate implicit in the liability component																5.60%
Carrying amount of liability	195,860,000	352,576,000															195,900,000	190,600,000
Unamortized discount																	34,100,000	39,400,000
Common stock based on initial conversion rate ratio (in shares)																	17.4092
Principal amount to be considered for conversion purpose																	1,000
Initial conversion price, per share																	$ 57.44
Maximum selling price of company's common stock																	150.00%
Principal amount of notes per average trading price																	$ 1,000
Maximum average conversion value of the Notes																	98.00%
Earliest conversion date																	June 15, 2016
Strike price of the call transaction (in dollars per share)																	$ 57.44
Strike price of warrant transactions (in dollars per share)																	$ 70.05
Debt instrument, call and warrant transactions descriptions																	In connection with the issuance of the 2016 Notes, the Company entered into call transactions and warrant transactions, primarily with affiliates of the initial purchasers of such notes (the “hedge participants”). The initial strike price of the call transaction is approximately $57.44 per share, subject to customary anti-dilution adjustments. The initial strike price of the warrant transaction is approximately $70.05 per share, subject to customary anti-dilution adjustments.
Termination of bond hedge contracts commencing 90 days after maturity of the Note (in days)																				100 days