ACQUISITIONS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business acquisition, shares issued		873,349
Share issue price per share		$ 18.79
Materials and supplies	$ 12,801	$ 14,078
Equipment and property, net	121,356	101,669
Goodwill	249,939	255,563	$ 211,847
Customer contracts	92,815	104,657
Other intangible assets	46,116	28,815
Current liabilities	252,986	252,679
Business Acquisitions [Member]
Accounts receivable, net	1,711	2,594
Materials and supplies	71	481
Equipment and property, net	948	4,516
Goodwill	196	48,477
Customer contracts	12,398	28,237
Other intangible assets	20,092	6,471
Current liabilities	(2,329)	(6,733)
Other assets and liabilities, net	460	(2,725)
Total consideration paid	33,547	81,318
Less: Common Stock Payment	0	(16,413)
Less: Contingent consideration liability	(85)	(1,570)
Total cash purchase price for the Company's acquisitions	$ 33,462	$ 63,335