GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Service revenues	$ 610,940	$ 584,562	$ 1,171,154	$ 1,114,793
Product revenues	141,848	112,948	270,575	218,800
Total revenues	752,788	697,510	1,441,729	1,333,593
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	412,356	388,684	803,443	762,670
Product cost of revenues	107,447	91,318	212,945	181,611
Total cost of revenues	519,803	480,002	1,016,388	944,281
Selling, general and administrative expenses	112,294	107,063	224,515	211,547
Accretion of environmental liabilities	2,416	2,548	4,706	5,053
Depreciation and amortization	71,531	73,393	143,943	142,295
(Loss) income from operations	46,744	34,504	52,177	30,417
Unrealized holding gains on available-for-sale investments	(833)	(189)	(2,382)	(539)
Loss on early extinguishment of debt	(6,045)	0	(6,045)	0
Gain on sale of business	31,722	0	31,722	0
Interest (expense) income	(22,492)	(21,647)	(45,068)	(40,627)
Equity in earnings of subsidiaries, net of taxes	0	0	0	0
Intercompany interest income (expense)	0	0	0	0
Income (loss) before (benefit) provision for income taxes	49,096	12,668	30,404	(10,749)
(Benefit) provision for income taxes	23,216	8,702	25,917	6,156
Net income (loss)	25,880	3,966	4,487	(16,905)
Other comprehensive income	15,098	(1,178)	21,149	44,659
Comprehensive income	40,978	2,788	25,636	27,754
Reportable Legal Entities | Clean Harbors, Inc.
Revenues:
Service revenues	0	0	0	0
Product revenues	0	0	0	0
Total revenues	0	0	0	0
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	0	(587)	0	(587)
Product cost of revenues	0	0	0	0
Total cost of revenues	0	(587)	0	(587)
Selling, general and administrative expenses	27	37	51	61
Accretion of environmental liabilities	0	0	0	0
Depreciation and amortization	0	0	0	0
(Loss) income from operations	(27)	550	(51)	526
Unrealized holding gains on available-for-sale investments	(76)	0	(222)	0
Loss on early extinguishment of debt	(6,045)		(6,045)
Gain on sale of business	0		0
Interest (expense) income	(22,614)	(22,962)	(45,273)	(43,105)
Equity in earnings of subsidiaries, net of taxes	43,167	17,413	35,530	8,642
Intercompany interest income (expense)	0	0	0	0
Income (loss) before (benefit) provision for income taxes	14,405	(4,999)	(16,061)	(33,937)
(Benefit) provision for income taxes	(11,475)	(8,965)	(20,548)	(17,032)
Net income (loss)	25,880	3,966	4,487	(16,905)
Other comprehensive income	15,098	(1,178)	21,149	44,659
Comprehensive income	40,978	2,788	25,636	27,754
Reportable Legal Entities | Guarantor Subsidiaries
Revenues:
Service revenues	474,801	456,013	918,106	884,490
Product revenues	125,859	95,648	242,509	185,236
Total revenues	600,660	551,661	1,160,615	1,069,726
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	306,960	292,343	601,105	575,307
Product cost of revenues	98,645	79,108	195,150	158,462
Total cost of revenues	405,605	371,451	796,255	733,769
Selling, general and administrative expenses	92,504	83,882	184,675	164,537
Accretion of environmental liabilities	2,181	2,313	4,236	4,603
Depreciation and amortization	51,937	50,696	103,837	99,391
(Loss) income from operations	48,433	43,319	71,612	67,426
Unrealized holding gains on available-for-sale investments	(406)	400	(1,795)	312
Loss on early extinguishment of debt	0		0
Gain on sale of business	31,722		31,722
Interest (expense) income	240	1,284	359	2,395
Equity in earnings of subsidiaries, net of taxes	(5,332)	(9,195)	(27,156)	(35,690)
Intercompany interest income (expense)	1,268	5,497	2,565	10,656
Income (loss) before (benefit) provision for income taxes	75,925	41,305	77,307	45,099
(Benefit) provision for income taxes	31,981	23,892	41,618	36,457
Net income (loss)	43,944	17,413	35,689	8,642
Other comprehensive income	15,098	(1,178)	21,149	44,659
Comprehensive income	59,042	16,235	56,838	53,301
Reportable Legal Entities | Non-Guarantor Subsidiaries
Revenues:
Service revenues	147,924	139,413	278,995	253,436
Product revenues	18,730	19,391	34,061	38,104
Total revenues	166,654	158,804	313,056	291,540
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	117,181	107,792	228,285	211,083
Product cost of revenues	11,543	14,301	23,790	27,689
Total cost of revenues	128,724	122,093	252,075	238,772
Selling, general and administrative expenses	19,763	23,144	39,789	46,949
Accretion of environmental liabilities	235	235	470	450
Depreciation and amortization	19,594	22,697	40,106	42,904
(Loss) income from operations	(1,662)	(9,365)	(19,384)	(37,535)
Unrealized holding gains on available-for-sale investments	(351)	(589)	(365)	(851)
Loss on early extinguishment of debt	0		0
Gain on sale of business	0		0
Interest (expense) income	(118)	31	(154)	83
Equity in earnings of subsidiaries, net of taxes	0	0	0	0
Intercompany interest income (expense)	(1,268)	(5,497)	(2,565)	(10,656)
Income (loss) before (benefit) provision for income taxes	(3,399)	(15,420)	(22,468)	(48,959)
(Benefit) provision for income taxes	2,710	(6,225)	4,847	(13,269)
Net income (loss)	(6,109)	(9,195)	(27,315)	(35,690)
Other comprehensive income	12,837	(597)	17,869	28,330
Comprehensive income	6,728	(9,792)	(9,446)	(7,360)
Consolidating Adjustments
Revenues:
Service revenues	(11,785)	(10,864)	(25,947)	(23,133)
Product revenues	(2,741)	(2,091)	(5,995)	(4,540)
Total revenues	(14,526)	(12,955)	(31,942)	(27,673)
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	(11,785)	(10,864)	(25,947)	(23,133)
Product cost of revenues	(2,741)	(2,091)	(5,995)	(4,540)
Total cost of revenues	(14,526)	(12,955)	(31,942)	(27,673)
Selling, general and administrative expenses	0	0	0	0
Accretion of environmental liabilities	0	0	0	0
Depreciation and amortization	0	0	0	0
(Loss) income from operations	0	0	0	0
Unrealized holding gains on available-for-sale investments	0	0	0	0
Loss on early extinguishment of debt	0		0
Gain on sale of business	0		0
Interest (expense) income	0	0	0	0
Equity in earnings of subsidiaries, net of taxes	(37,835)	(8,218)	(8,374)	27,048
Intercompany interest income (expense)	0	0	0	0
Income (loss) before (benefit) provision for income taxes	(37,835)	(8,218)	(8,374)	27,048
(Benefit) provision for income taxes	0	0	0	0
Net income (loss)	(37,835)	(8,218)	(8,374)	27,048
Other comprehensive income	(27,935)	1,775	(39,018)	(72,989)
Comprehensive income	$ (65,770)	$ (6,443)	$ (47,392)	$ (45,941)