GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2011
Condensed consolidating statement of cash flows
Proceeds from sale of long-term investments	$ 0	$ 1,000
Payments to Acquire Interest in Subsidiaries and Affiliates		0
Net cash from operating activities	232,692	151,336
Cash flows from investing activities:
Additions to property, plant and equipment	(130,326)	(113,644)
Proceeds from slales of fixed assets	4,190	5,925
Acquisitions, net of cash acquired	(92,475)	(336,960)
Costs to obtain or renew permits	(2,409)	(2,356)
Proceeds from Sale and Maturity of Available-for-sale Securities	0	425
Purchase of marketable securities	(10,517)	0
Other	5,120	0
Net cash used in investing activities	(226,417)	(445,610)
Cash flows from financing activities:
Change in uncashed checks	(13,955)	(2,580)
Proceeds from exercise of stock options	231	1,089
Proceeds from employee stock purchase plan	4,627	2,451
Remittance of shares, net	(1,604)	(1,897)
Excess tax benefit of stock-based compensation	1,786	1,949
Deferred financing costs paid	(9,638)	(8,442)
Payments on capital leases	(5,303)	(5,775)
Principal payment on debt	(520,000)	0
Proceeds from Issuance of Senior Long-term Debt	800,000
Distribution of cash earned on employee participation plan	(55)	(189)
Proceeds from Issuance of Secured Debt	0	261,250
Dividends (paid) / received	0	0
Interest (payments) / received	0	0
Proceeds from Intercompany Debt		0
Net cash from financing activities	256,089	247,856
Effect of exchange rate change on cash	527	1,367
(Decrease) increase in cash and cash equivalents	262,891	(45,051)
Cash and cash equivalents, beginning of period	260,723	302,210	257,159
Cash and cash equivalents, end of period	523,614	257,159	257,159
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Proceeds from sale of long-term investments		0
Payments to Acquire Interest in Subsidiaries and Affiliates		258,597
Net cash from operating activities	(49,918)	(16,908)
Cash flows from investing activities:
Additions to property, plant and equipment	0	0
Proceeds from slales of fixed assets	0	0
Acquisitions, net of cash acquired	0	0
Costs to obtain or renew permits	0	0
Proceeds from Sale and Maturity of Available-for-sale Securities		0
Purchase of marketable securities	0
Other	0
Net cash used in investing activities	0	(258,597)
Cash flows from financing activities:
Change in uncashed checks	0	0
Proceeds from exercise of stock options	231	1,089
Proceeds from employee stock purchase plan	4,627	2,451
Remittance of shares, net	(1,604)	(1,897)
Excess tax benefit of stock-based compensation	1,786	1,949
Deferred financing costs paid	(9,638)	(8,442)
Payments on capital leases	0	0
Distribution of cash earned on employee participation plan	(55)	0
Proceeds from Issuance of Secured Debt		261,250
Dividends (paid) / received	10,010	10,186
Interest (payments) / received	0	0
Proceeds from Intercompany Debt		0
Net cash from financing activities	285,357	266,586
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	235,439	(8,919)
Cash and cash equivalents, beginning of period	91,581	100,476
Cash and cash equivalents, end of period	327,020	91,557
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Proceeds from sale of long-term investments		1,000
Payments to Acquire Interest in Subsidiaries and Affiliates		(178,884)
Net cash from operating activities	98,497	77,653
Cash flows from investing activities:
Additions to property, plant and equipment	(75,664)	(75,274)
Proceeds from slales of fixed assets	3,411	545
Acquisitions, net of cash acquired	(51,424)	(50,166)
Costs to obtain or renew permits	(625)	(486)
Proceeds from Sale and Maturity of Available-for-sale Securities		0
Purchase of marketable securities	0
Other	603
Net cash used in investing activities	(123,699)	54,503
Cash flows from financing activities:
Change in uncashed checks	(7,771)	(1,363)
Proceeds from exercise of stock options	0	0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net	0	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid	0	0
Payments on capital leases	(781)	(532)
Principal payment on debt	0
Proceeds from Issuance of Senior Long-term Debt	0
Distribution of cash earned on employee participation plan	0	0
Proceeds from Issuance of Secured Debt		0
Dividends (paid) / received	(23,669)	(24,306)
Interest (payments) / received	43,954	35,088
Proceeds from Intercompany Debt		(120,475)
Net cash from financing activities	11,733	(111,588)
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(13,469)	20,568
Cash and cash equivalents, beginning of period	128,071	124,582
Cash and cash equivalents, end of period	114,602	145,150
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Proceeds from sale of long-term investments		0
Payments to Acquire Interest in Subsidiaries and Affiliates		(79,713)
Net cash from operating activities	184,113	90,591
Cash flows from investing activities:
Additions to property, plant and equipment	(54,662)	(38,370)
Proceeds from slales of fixed assets	779	5,380
Acquisitions, net of cash acquired	(41,051)	(286,794)
Costs to obtain or renew permits	(1,784)	(1,870)
Proceeds from Sale and Maturity of Available-for-sale Securities		425
Purchase of marketable securities	(10,517)
Other	4,517
Net cash used in investing activities	(102,718)	(241,516)
Cash flows from financing activities:
Change in uncashed checks	(6,184)	(1,217)
Proceeds from exercise of stock options	0	0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net	0	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid	0	0
Payments on capital leases	(4,522)	(5,243)
Principal payment on debt	0
Proceeds from Issuance of Senior Long-term Debt	0
Distribution of cash earned on employee participation plan	0	(189)
Proceeds from Issuance of Secured Debt		0
Dividends (paid) / received	13,659	14,120
Interest (payments) / received	(43,954)	(35,088)
Proceeds from Intercompany Debt		120,475
Net cash from financing activities	(41,001)	92,858
Effect of exchange rate change on cash	527	1,367
(Decrease) increase in cash and cash equivalents	40,921	(56,700)
Cash and cash equivalents, beginning of period	41,071	77,152
Cash and cash equivalents, end of period	$ 81,992	$ 20,452