GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 179,531	$ 224,108	$ 93,270
Cash flows from investing activities:
Additions to property, plant and equipment	(148,513)	(116,450)	(62,244)
Acquisitions, net of cash acquired	(336,960)	(14,646)	(54,476)
Additions to intangible assets, including costs to obtain or renew permits	(2,927)	(4,204)	(2,228)
Purchased of marketable securities	0	(2,127)	0
Purshase of investment securities	0	(10,506)	0
Proceeds from sales of fixed assets and assets held for sale	6,794	16,053	452
Proceeds from sales of marketable securities	425	3,557	105
Proceeds from sale of long-term investments	1,000	1,300	0
Proceeds from insurance settlement	0	1,336	0
Investment in subsidiaries	0	0	0
Net cash from investing activities	(480,181)	(125,687)	(118,391)
Cash flows from financing activities:
Change in uncashed checks	9,822	(1,266)	4,034
Proceeds from exercise of stock options	1,350	862	430
Proceeds from employee stock purchase plan	3,516	2,449	2,315
Remittance of shares, net	(4,061)	(399)	(415)
Excess tax benefit of stock-based compensation	3,352	1,751	481
Deferred financing costs paid	(8,463)	(353)	(10,473)
Payments on capital leases	(7,837)	(5,126)	(1,118)
Repayments of Long-term Debt	0	0	(230,745)
Principal payment on debt	0	(30,000)	(53,032)
Distribution of cash earned on employee participation plan	(189)	(148)	0
Issuance of senior secured notes, including premium	261,250	0	292,107
Interest (payments) / received	0	0	0
Intercompany debt	0	0	0
Intercompany financing			0
Dividends (paid) / received			0
Net cash from financing activities	258,740	(32,230)	3,584
Effect of exchange rate change on cash	423	2,473	5,559
Increase in cash and cash equivalents	(41,487)	68,664	(15,978)
Cash and cash equivalents, beginning of period	302,210	233,546	249,524
Cash and cash equivalents, end of period	260,723	302,210	233,546
Dividends (paid) / received	0
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	(17,428)	(4,666)	33,494
Cash flows from investing activities:
Additions to property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	0	0	(402)
Additions to intangible assets, including costs to obtain or renew permits	0	0	0
Purchased of marketable securities		0
Purshase of investment securities		(10,506)
Proceeds from sales of fixed assets and assets held for sale	0	0	0
Proceeds from sales of marketable securities	0	0	0
Proceeds from sale of long-term investments	0	0
Proceeds from insurance settlement		0
Investment in subsidiaries	(258,597)	(236,700)	(378,520)
Net cash from investing activities	(258,597)	(247,206)	(378,922)
Cash flows from financing activities:
Change in uncashed checks	0	0	0
Proceeds from exercise of stock options	1,350	862	430
Proceeds from employee stock purchase plan	3,516	2,449	2,315
Remittance of shares, net	(4,061)	(399)	(415)
Excess tax benefit of stock-based compensation	3,352	1,751	481
Deferred financing costs paid	(8,463)	(353)	(10,473)
Payments on capital leases	0	0	0
Repayments of Long-term Debt			0
Principal payment on debt		(30,000)	(53,032)
Distribution of cash earned on employee participation plan	0	0
Issuance of senior secured notes, including premium	261,250		292,107
Interest (payments) / received	0	0	0
Intercompany debt	0	236,700	(222,040)
Intercompany financing			118,800
Dividends (paid) / received			236,699
Net cash from financing activities	267,130	211,010	364,872
Effect of exchange rate change on cash	0	0	0
Increase in cash and cash equivalents	(8,895)	(40,862)	19,444
Cash and cash equivalents, beginning of period	100,476	141,338	121,894
Cash and cash equivalents, end of period	91,581	100,476	141,338
Dividends (paid) / received	10,186
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	90,015	125,974	33,952
Cash flows from investing activities:
Additions to property, plant and equipment	(92,531)	(55,814)	(49,628)
Acquisitions, net of cash acquired	(50,166)	(14,646)	0
Additions to intangible assets, including costs to obtain or renew permits	(465)	(1,534)	(896)
Purchased of marketable securities		0
Purshase of investment securities		0
Proceeds from sales of fixed assets and assets held for sale	657	1,018	298
Proceeds from sales of marketable securities	0	0	0
Proceeds from sale of long-term investments	1,000	1,300
Proceeds from insurance settlement		0
Investment in subsidiaries	178,884	236,700	237,442
Net cash from investing activities	37,379	167,024	187,216
Cash flows from financing activities:
Change in uncashed checks	6,558	(995)	565
Proceeds from exercise of stock options	0	0	0
Proceeds from employee stock purchase plan	0	0	0
Remittance of shares, net	0	0	0
Excess tax benefit of stock-based compensation	0	0	0
Deferred financing costs paid	0	0	0
Payments on capital leases	(820)	(492)	(384)
Repayments of Long-term Debt			0
Principal payment on debt		0	0
Distribution of cash earned on employee participation plan	0	0
Issuance of senior secured notes, including premium			0
Interest (payments) / received	35,088	19,363	22,228
Intercompany debt	(140,425)	(236,700)	0
Intercompany financing			(402)
Dividends (paid) / received			(260,701)
Net cash from financing activities	(123,905)	(218,824)	(238,694)
Effect of exchange rate change on cash	0	0	0
Increase in cash and cash equivalents	3,489	74,174	(17,526)
Cash and cash equivalents, beginning of period	124,582	50,408	67,934
Cash and cash equivalents, end of period	128,071	124,582	50,408
Dividends (paid) / received	(24,306)
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	106,944	102,800	25,824
Cash flows from investing activities:
Additions to property, plant and equipment	(55,982)	(60,636)	(12,616)
Acquisitions, net of cash acquired	(286,794)	0	(54,074)
Additions to intangible assets, including costs to obtain or renew permits	(2,462)	(2,670)	(1,332)
Purchased of marketable securities		(2,127)
Purshase of investment securities		0
Proceeds from sales of fixed assets and assets held for sale	6,137	15,035	154
Proceeds from sales of marketable securities	425	3,557	105
Proceeds from sale of long-term investments	0	0
Proceeds from insurance settlement		1,336
Investment in subsidiaries	79,713	0	141,078
Net cash from investing activities	(258,963)	(45,505)	73,315
Cash flows from financing activities:
Change in uncashed checks	3,264	(271)	3,469
Proceeds from exercise of stock options	0	0	0
Proceeds from employee stock purchase plan	0	0	0
Remittance of shares, net	0	0	0
Excess tax benefit of stock-based compensation	0	0	0
Deferred financing costs paid	0	0	0
Payments on capital leases	(7,017)	(4,634)	(734)
Repayments of Long-term Debt			(230,745)
Principal payment on debt		0	0
Distribution of cash earned on employee participation plan	(189)	(148)
Issuance of senior secured notes, including premium			0
Interest (payments) / received	(35,088)	(19,363)	(22,228)
Intercompany debt	140,425	0	222,040
Intercompany financing			(118,398)
Dividends (paid) / received			24,002
Net cash from financing activities	115,515	(24,416)	(122,594)
Effect of exchange rate change on cash	423	2,473	5,559
Increase in cash and cash equivalents	(36,081)	35,352	(17,896)
Cash and cash equivalents, beginning of period	77,152	41,800	59,696
Cash and cash equivalents, end of period	41,071	77,152	41,800
Dividends (paid) / received	$ 14,120