SUPPLEMENTAL CASH FLOW INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
SUPPLEMENTAL CASH FLOW INFORMATION [Abstract]
Accrued but unpaid additions to property and equipment at December 31	$ 41,754	$ 66,764	$ 40,345
Value of common stock issued in exchange for SKDP shares	0	0	337,907
Cash interest payments in excess of (less than) interest capitalized	44,579	14,802	23,596
Cash income tax payments, net of refunds	$ 13,150	$ 276,839	$ 98,979