GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Details 4) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 151,336	$ 153,930
Cash flows from investing activities:
Additions to property, plant and equipment	(113,644)	(74,741)
Acquisitions, net of cash acquired	(336,960)	(13,846)
Additions to intangible assets, including costs to obtain or renew permits	(2,356)	(3,262)
Purchase of available for sale securities	0	(1,486)
Proceeds from sales of fixed assets and assets held for sale	5,925	15,963
Proceeds from sales of marketable securities	425	2,627
Proceeds from sale of long-term investments	1,000	1,300
Proceeds from insurance settlement	0	1,336
Investment in subsidiaries	0	0
Net cash used in investing activities	(445,610)	(72,109)
Cash flows from financing activities:
Change in uncashed checks	(2,580)	(4,682)
Proceeds from exercise of stock options	1,089	550
Proceeds from employee stock purchase plan	2,451	1,769
Remittance of shares, net	(1,897)	(198)
Excess tax benefit of stock-based compensation	1,949	1,221
Deferred financing costs paid	(8,442)	(53)
Payments on capital leases	(5,775)	(3,361)
Principal payment on debt	0	(30,000)
Distribution of cash earned on employee participation plan	(189)	(148)
Issuance of senior secured notes, including premium	261,250	0
Dividends (paid) / received	0
Interest (payments) / received	0	0
Intercompany debt	0	0
Net cash from financing activities	247,856	(34,902)
Effect of exchange rate change on cash	1,367	451
(Decrease) increase in cash and cash equivalents	(45,051)	47,370
Cash and cash equivalents, beginning of period	302,210	233,546
Cash and cash equivalents, end of period	257,159	280,916
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	(16,908)	(3,688)
Cash flows from investing activities:
Additions to property, plant and equipment	0	0
Acquisitions, net of cash acquired	0	0
Additions to intangible assets, including costs to obtain or renew permits	0	0
Purchase of available for sale securities		0
Proceeds from sales of fixed assets and assets held for sale	0	0
Proceeds from sales of marketable securities	0	0
Proceeds from sale of long-term investments	0	0
Proceeds from insurance settlement		0
Investment in subsidiaries	(258,597)	(236,700)
Net cash used in investing activities	(258,597)	(236,700)
Cash flows from financing activities:
Change in uncashed checks	0	0
Proceeds from exercise of stock options	1,089	550
Proceeds from employee stock purchase plan	2,451	1,769
Remittance of shares, net	(1,897)	(198)
Excess tax benefit of stock-based compensation	1,949	1,221
Deferred financing costs paid	(8,442)	(53)
Payments on capital leases	0	0
Principal payment on debt		(30,000)
Distribution of cash earned on employee participation plan	0	0
Issuance of senior secured notes, including premium	261,250
Dividends (paid) / received	10,186
Interest (payments) / received	0	0
Intercompany debt	0	236,700
Net cash from financing activities	266,586	209,989
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(8,919)	(30,399)
Cash and cash equivalents, beginning of period	100,476	141,338
Cash and cash equivalents, end of period	91,557	110,939
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	77,653	100,673
Cash flows from investing activities:
Additions to property, plant and equipment	(75,274)	(42,501)
Acquisitions, net of cash acquired	(50,166)	(13,846)
Additions to intangible assets, including costs to obtain or renew permits	(486)	(1,203)
Purchase of available for sale securities		0
Proceeds from sales of fixed assets and assets held for sale	545	997
Proceeds from sales of marketable securities	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
Net cash used in investing activities	54,503	181,447
Cash flows from financing activities:
Change in uncashed checks	(1,363)	(1,347)
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	(532)	(284)
Principal payment on debt		0
Distribution of cash earned on employee participation plan	0	0
Issuance of senior secured notes, including premium	0
Dividends (paid) / received	(24,306)
Interest (payments) / received	35,088	19,363
Intercompany debt	(120,475)	(236,700)
Net cash from financing activities	(111,588)	(218,968)
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	20,568	63,152
Cash and cash equivalents, beginning of period	124,582	50,408
Cash and cash equivalents, end of period	145,150	113,560
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	90,591	56,945
Cash flows from investing activities:
Additions to property, plant and equipment	(38,370)	(32,240)
Acquisitions, net of cash acquired	(286,794)	0
Additions to intangible assets, including costs to obtain or renew permits	(1,870)	(2,059)
Purchase of available for sale securities		(1,486)
Proceeds from sales of fixed assets and assets held for sale	5,380	14,966
Proceeds from sales of marketable securities	425	2,627
Proceeds from sale of long-term investments	0	0
Proceeds from insurance settlement		1,336
Investment in subsidiaries	79,713	0
Net cash used in investing activities	(241,516)	(16,856)
Cash flows from financing activities:
Change in uncashed checks	(1,217)	(3,335)
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	(5,243)	(3,077)
Principal payment on debt		0
Distribution of cash earned on employee participation plan	(189)	(148)
Issuance of senior secured notes, including premium	0
Dividends (paid) / received	14,120
Interest (payments) / received	(35,088)	(19,363)
Intercompany debt	120,475	0
Net cash from financing activities	92,858	(25,923)
Effect of exchange rate change on cash	1,367	451
(Decrease) increase in cash and cash equivalents	(56,700)	14,617
Cash and cash equivalents, beginning of period	77,152	41,800
Cash and cash equivalents, end of period	$ 20,452	$ 56,417