GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Details 4) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 75,629	$ 97,317
Cash flows from investing activities:
Additions to property, plant and equipment	(65,460)	(35,490)
Acquisitions, net of cash acquired	(205,922)	(13,751)
Additions to intangible assets, including costs to obtain or renew permits	(1,066)	(2,192)
Proceeds from sales of fixed assets and assets held for sale	4,891	15,594
Proceeds from sales of marketable securities	388	2,575
Proceeds from sale of long-term investments		1,300
Proceeds from insurance settlement		1,336
Net cash used in investing activities	(267,169)	(30,628)
Cash flows from financing activities:
Change in uncashed checks	13,746	(3,600)
Proceeds from exercise of stock options	783	318
Proceeds from employee stock purchase plan	1,556	1,187
Remittance of shares, net	(1,807)	(113)
Excess tax benefit of stock-based compensation	1,617	782
Deferred financing costs paid	(8,099)	(53)
Payments on capital leases	(3,316)	(1,752)
Distribution of cash earned on employee participation plan	(189)	(148)
Issuance of senior secured notes, including premium	261,250
Net cash from financing activities	265,541	(3,379)
Effect of exchange rate change on cash	1,365	(1,556)
Increase in cash and cash equivalents	75,366	61,754
Cash and cash equivalents, beginning of period	302,210	233,546
Cash and cash equivalents, end of period	377,576	295,300
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	4,474	(155)
Cash flows from investing activities:
Investment in subsidiaries	(173,540)	(236,700)
Net cash used in investing activities	(173,540)	(236,700)
Cash flows from financing activities:
Proceeds from exercise of stock options	783	318
Proceeds from employee stock purchase plan	1,556	1,187
Remittance of shares, net	(1,807)	(113)
Excess tax benefit of stock-based compensation	1,617	782
Deferred financing costs paid	(8,099)	(53)
Issuance of senior secured notes, including premium	261,250
Dividends (paid) / received	10,186
Intercompany debt		236,700
Net cash from financing activities	265,486	238,821
Increase in cash and cash equivalents	96,420	1,966
Cash and cash equivalents, beginning of period	100,476	141,338
Cash and cash equivalents, end of period	196,896	143,304
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	28,763	65,613
Cash flows from investing activities:
Additions to property, plant and equipment	(40,991)	(17,535)
Acquisitions, net of cash acquired		(13,751)
Additions to intangible assets, including costs to obtain or renew permits	(298)	(946)
Proceeds from sales of fixed assets and assets held for sale	361	930
Proceeds from sale of long-term investments		1,300
Investment in subsidiaries	115,784	236,700
Net cash used in investing activities	74,856	206,698
Cash flows from financing activities:
Change in uncashed checks	11,329	(1,317)
Payments on capital leases	(318)	(79)
Dividends (paid) / received	(24,306)
Interest (payments) / received	24,132	9,136
Intercompany debt	(120,475)	(236,700)
Net cash from financing activities	(109,638)	(228,960)
Increase in cash and cash equivalents	(6,019)	43,351
Cash and cash equivalents, beginning of period	124,582	50,408
Cash and cash equivalents, end of period	118,563	93,759
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	42,392	31,859
Cash flows from investing activities:
Additions to property, plant and equipment	(24,469)	(17,955)
Acquisitions, net of cash acquired	(205,922)
Additions to intangible assets, including costs to obtain or renew permits	(768)	(1,246)
Proceeds from sales of fixed assets and assets held for sale	4,530	14,664
Proceeds from sales of marketable securities	388	2,575
Proceeds from insurance settlement		1,336
Investment in subsidiaries	57,756
Net cash used in investing activities	(168,485)	(626)
Cash flows from financing activities:
Change in uncashed checks	2,417	(2,283)
Payments on capital leases	(2,998)	(1,673)
Distribution of cash earned on employee participation plan	(189)	(148)
Dividends (paid) / received	14,120
Interest (payments) / received	(24,132)	(9,136)
Intercompany debt	120,475
Net cash from financing activities	109,693	(13,240)
Effect of exchange rate change on cash	1,365	(1,556)
Increase in cash and cash equivalents	(15,035)	16,437
Cash and cash equivalents, beginning of period	77,152	41,800
Cash and cash equivalents, end of period	$ 62,117	$ 58,237