COMMITMENTS AND CONTINGENCIES (Summary Of Standby Letters Of Credit) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Standby Letters of Credit
Long term debt	[1]	$ 1,907,861		$ 1,984,779	$ 1,983,477
Reclamation/restoration requirements		234,919	$ 238,689	$ 226,565	$ 225,117	$ 225,831	$ 228,234
Standby Letters of Credit [Member]
Standby Letters of Credit
Risk management insurance		33,111
Reclamation/restoration requirements		5,878
Total		53,219
Industrial revenue bonds [Member] | Standby Letters of Credit [Member]
Standby Letters of Credit
Long term debt		$ 14,230

[1] The debt balances as of December 31, 2014 and June 30, 2014 have been adjusted to reflect our early adoption of ASU 2015-03 and related election as disclosed in Note 17.