DEBT (Details) (USD $)	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2012
Long-term debt disclosure
Total debt, non-current	$ 293,248,000	$ 297,697,000	$ 297,697,000
Convertible notes due 2019, net
Long-term debt disclosure
Total debt, non-current	293,248,000	297,697,000	297,697,000
Aggregate principal amount of convertible senior notes issued	370,000,000
Interest rate on convertible senior notes (as a percent)		2.875%	2.875%
Interest expense recognized		5,200,000	10,300,000
Revolving credit facility
Long-term debt disclosure
Maximum availability under the revolving credit facility		$ 350,000,000	$ 350,000,000