INTEREST EXPENSE Schedule of extinguishment of debt (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Extinguishment of Debt [Line Items]
Loss on extinguishment	$ 198	$ 25,904	$ 5,299
2013 Convertible Notes [Member]
Extinguishment of Debt [Line Items]
Loss on extinguishment	3,763	23,516	724
2014 Floating Rate Notes [Member]
Extinguishment of Debt [Line Items]
Loss on extinguishment	(3,565)	0	(485)
2016 Fixed Rate Notes [Member]
Extinguishment of Debt [Line Items]
Loss on extinguishment	0	2,388	1,509
Credit Facility [Domain]
Extinguishment of Debt [Line Items]
Loss on extinguishment	$ 0	$ 0	$ 3,551