OPERATING LEASES (Tables)

12 Months Ended

Dec. 31, 2015

OPERATING LEASES [Abstract]

Rental Expense from Continuing Operations under Nonmineral Operating Leases

in thousands	2015	2014	2013
Operating Leases
Minimum rentals	$        49,461	$       42,887	$       40,151
Contingent rentals (based principally on usage)	60,380	56,717	44,111
Total	$      109,841	$       99,604	$       84,262

Future Minimum Operating Lease Payments

in thousands
Future Minimum Operating Lease Payments
2016	$        30,945
2017	29,712
2018	26,543
2019	22,455
2020	20,508
Thereafter	128,657
Total	$      258,820