DEBT (Additional Information) (Detail) (USD $)					9 Months Ended											3 Months Ended				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Revolving Credit Facility	Dec. 31, 2012 Revolving Credit Facility	Sep. 30, 2013 Revolving Credit Facility Option (ii), (x)	Sep. 30, 2013 Revolving Credit Facility Option (ii), (z)	Sep. 30, 2013 Revolving Credit Facility Minimum	Sep. 30, 2013 Revolving Credit Facility Minimum Option (i)	Sep. 30, 2013 Revolving Credit Facility Maximum	Sep. 30, 2013 Revolving Credit Facility Maximum Option (i)	Sep. 30, 2013 Revolving Credit Facility August 2010 Amendment	Sep. 30, 2013 Revolving Credit Facility June 2011 Amendment	Sep. 30, 2013 Revolving Credit Facility June 2011 Amendment Minimum	Sep. 30, 2013 Revolving Credit Facility June 2011 Amendment Maximum	Sep. 30, 2013 Revolving Credit Facility May 2012 Amendment Maximum	Sep. 30, 2013 Revolving Credit Facility June 2013 Amendment	Sep. 30, 2013 Revolving Credit Facility June 2013 Amendment Maximum	Sep. 30, 2013 Revolving Credit Facility June 2013 Amendment Leverage Ratio after March 31, 2015	Sep. 30, 2013 Revolving Credit Facility June 2013 Amendment Maximum Levarage Ratio July 01, 2014 through March 31.2015	Sep. 30, 2013 2016 Convertible Senior Notes	Dec. 31, 2012 2016 Convertible Senior Notes	Jun. 15, 2011 2016 Convertible Senior Notes
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity													$ 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
Leverage ratio															3.75		4.25	3.75	4.00
Debt issuance costs																1,100,000
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			341,900,000	321,900,000
Weighted average interest rate on debt			1.90%	1.80%
Available borrowings under senior secured revolving credit facility			258,100,000
Fair value of outstanding borrowings			337,000,000																	237,600,000
Principal amount outstanding																				230,000,000	230,000,000	230,000,000
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	203,265,000	197,672,000																		203,300,000	197,700,000
Unamortized discount																				26,700,000	32,300,000
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