COMMITMENTS AND CONTINGENCIES (Summary Of Standby Letters Of Credit) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Standby Letters of Credit
Long term debt	$ 2,006,537		$ 2,522,413	$ 2,524,581
Reclamation/restoration requirements	225,117	225,831	228,234	222,851	156,458	150,072
Standby Letters of Credit [Member]
Standby Letters of Credit
Risk management insurance	32,839
Reclamation/restoration requirements	6,199
Total	53,268
Industrial revenue bonds | Standby Letters of Credit [Member]
Standby Letters of Credit
Long term debt	$ 14,230