ACQUISITIONS - TOTAL ASSETS ACQUIRED AND LIABILITES ASSUMED FROM MIDWEST FRANC AND SAND LLC (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
	Jul. 25, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Gain (loss) on settlement of pre-existing agreements			$ 0	$ (689)	$ 0
Midwest Frac and Sands LLC
Business Acquisition [Line Items]
Cash deposit	$ 11,000	$ 11,000
Present value of purchase obligation	11,226
Present value of contingent consideration	853
Gain (loss) on settlement of pre-existing agreements	(689)
Total consideration	22,390
Mineral reserves	19,381
Other property, plant and equipment	4,403
Non-compete agreement	100
Total assets acquired	23,884
Governmental highway improvement obligation	1,128
Asset retirement obligation	227
Accounts payable	139
Net assets acquired	$ 22,390