SEGMENT REPORTING (Segment Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total revenues	$ 692,113	$ 729,520	$ 697,510	$ 636,083	$ 713,044	$ 893,366	$ 936,228	$ 732,499	$ 2,755,226	$ 3,275,137	$ 3,401,636
Property, plant and equipment, net	1,611,827				1,532,467				1,611,827	1,532,467
Permits and other intangibles, net	498,721				506,818				498,721	506,818
Goodwill	465,154				453,105				465,154	453,105	452,669
Goodwill and Permits and other intangibles, net	963,875				959,923				963,875	959,923
Assets	3,681,920				3,431,428				3,681,920	3,431,428	3,689,423
Technical Services
Total revenues									906,495	991,410	1,043,267
Property, plant and equipment, net	521,134				483,425				521,134	483,425
Permits and other intangibles, net	78,625				73,601				78,625	73,601
Goodwill	61,116				49,267				61,116	49,267	50,092
Goodwill and Permits and other intangibles, net	139,741				122,868				139,741	122,868
Assets	862,957				800,060				862,957	800,060	756,169
Industrial and Field Services
Total revenues									618,245	1,023,638	795,249
Property, plant and equipment, net	245,143				283,509				245,143	283,509
Permits and other intangibles, net	17,817				17,198				17,817	17,198
Goodwill	107,968				105,286				107,968	105,286	109,214
Goodwill and Permits and other intangibles, net	125,785				122,484				125,785	122,484
Assets	446,826				461,180				446,826	461,180	513,962
Safety-Kleen
Total revenues									1,110,727	1,060,926	1,200,907
Property, plant and equipment, net	584,647				458,394				584,647	458,394
Permits and other intangibles, net	391,390				396,661				391,390	396,661
Goodwill	296,070				266,344				296,070	266,344	224,756
Goodwill and Permits and other intangibles, net	687,460				663,005				687,460	663,005
Assets	1,474,755				1,297,971				1,474,755	1,297,971	1,269,993
Oil, Gas and Lodging Services
Total revenues									116,692	198,705	361,937
Property, plant and equipment, net	182,038				215,645				182,038	215,645
Permits and other intangibles, net	10,889				19,358				10,889	19,358
Goodwill	0				32,208				0	32,208	68,607
Goodwill and Permits and other intangibles, net	10,889				51,566				10,889	51,566
Assets	253,242				333,245				253,242	333,245	471,695
Corporate Items
Total revenues									3,067	458	276
Property, plant and equipment, net	78,865				91,494				78,865	91,494
Assets	644,140				538,972				644,140	538,972	677,604
United States and Puerto Rico
Total revenues									$ 2,213,400	$ 2,576,200	$ 2,414,600
Percent of revenues									80.30%	78.70%	71.00%
United States
Assets	2,960,337				2,575,746				$ 2,960,337	$ 2,575,746	$ 2,557,639
Canada
Total revenues									$ 538,000	$ 695,000	$ 982,100
Percent of revenues									19.50%	21.20%	28.90%
Property, plant and equipment, net	$ 400,300				$ 449,300				$ 400,300	$ 449,300
Percent of property, plant and equipment, net	24.80%				29.30%				24.80%	29.30%
Permits and other intangibles, net	$ 63,100				$ 71,700				$ 63,100	$ 71,700
Percent of permits and other intangibles, net	12.70%				14.20%				12.70%	14.20%
Assets	$ 721,583				$ 851,949				$ 721,583	$ 851,949	$ 1,128,458
Other foreign
Percent of revenues									1.00%	1.00%	1.00%
Assets	$ 0				$ 3,733				$ 0	$ 3,733	$ 3,326