DEBT (Summary of Debt) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Long Term Debt
Long-term Debt, Total	$ 2,522,413,000		$ 2,677,003,000
Less current maturities	170,000		150,602,000
Total long-term debt	2,522,243,000		2,526,401,000
Estimated fair value of long-term debt	2,820,399,000		2,766,835,000
6.30% notes due 2013
Long Term Debt
Long-term Debt, Total	0	[1]	140,413,000	[1]
10.125% notes due 2015
Long Term Debt
Long-term Debt, Total	151,897,000	[2]	152,718,000	[2]
6.50% notes due 2016
Long Term Debt
Long-term Debt, Total	511,627,000	[3]	515,060,000	[3]
6.40% notes due 2017
Long Term Debt
Long-term Debt, Total	349,907,000	[4]	349,888,000	[4]
7.00% notes due 2018
Long Term Debt
Long-term Debt, Total	399,772,000	[5]	399,731,000	[5]
10.375% notes due 2018
Long Term Debt
Long-term Debt, Total	248,843,000	[6]	248,676,000	[6]
7.50% notes due 2021
Long Term Debt
Long-term Debt, Total	600,000,000	[7]	600,000,000	[7]
7.15% notes due 2037
Long Term Debt
Long-term Debt, Total	239,561,000	[8]	239,553,000	[8]
Medium-term notes
Long Term Debt
Long-term Debt, Total	6,000,000		16,000,000
Municipal Bonds
Long Term Debt
Long-term Debt, Total	14,000,000		14,000,000
Other notes
Long Term Debt
Long-term Debt, Total	$ 806,000		$ 964,000

[1] Includes decreases for unamortized discounts, as follows: December 31, 2012 — $30 thousand.

[2] Includes an increase for the unamortized portion of the deferred gain realized upon the August 2011 settlement of interest rate swaps, as follows: December 31, 2013 — $2,082 thousand and December 31, 2012 — $2,983 thousand. Additionally, includes decreases for unamortized discounts as follows: December 31, 2013 — $185 thousand and December 31, 2012 — $265 thousand. The effective interest rate for these notes is 9.59%.

[3] Includes an increase for the unamortized portion of the deferred gain realized upon the August 2011 settlement of interest rate swaps, as follows: December 31, 2013 — $11,627 thousand and December 31, 2012 — $15,060 thousand. The effective interest rate for these notes is 6.02%.

[4] Includes decreases for unamortized discounts, as follows: December 31, 2013 — $93 thousand and December 31, 2012 — $112 thousand. The effective interest rate for these notes is 7.41%.

[5] Includes decreases for unamortized discounts, as follows: December 31, 2013 — $228 thousand and December 31, 2012 — $269 thousand. The effective interest rate for these notes is 7.87%.

[6] Includes decreases for unamortized discounts, as follows: December 31, 2013 — $1,157 thousand and December 31, 2012 — $1,324 thousand. The effective interest rate for these notes is 10.62%.

[7] The effective interest rate for these notes is 7.75%.

[8] Includes decreases for unamortized discounts, as follows: December 31, 2013 — $627 thousand and December 31, 2012 — $635 thousand. The effective interest rate for these notes is 8.05%.