GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 29,553	$ 14,856
Cash flows from investing activities:
Additions to property, plant and equipment	(27,661)	(34,115)
Proceeds from slales of fixed assets	425	1,013
Acquisitions, net of cash acquired	(8,751)	(2,152)
Costs to obtain or renew permits	(425)	(322)
Proceeds from sales of marketable securities	0	388
Purchase of available for sale securities	(4,468)	0
Other	5,120	0
Net cash used in investing activities	(35,760)	(35,188)
Cash flows from financing activities:
Change in uncashed checks	(13,576)	(5,216)
Proceeds from exercise of stock options	30	39
Proceeds from employee stock purchase plan	1,238	699
Remittance of shares, net	0	(1,784)
Excess tax benefit of stock-based compensation	713	1,105
Deferred financing costs paid	0	(5,628)
Payments on capital leases	(2,166)	(1,690)
Distribution of cash earned on employee participation plan	(38)	(189)
Issuance of senior secured notes, including premium	0	261,250
Dividends (paid) / received	0	0
Interest (payments) / received	0	0
Net cash from financing activities	(13,799)	248,586
Effect of exchange rate change on cash	810	1,299
(Decrease) increase in cash and cash equivalents	(19,196)	229,553
Cash and cash equivalents, beginning of period	260,723	302,210
Cash and cash equivalents, end of period	241,527	531,763
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	(18,010)	2,898
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 sales of marketable securities		0
Purchase of available for sale securities	0
Other	0
Net cash used in investing activities	0	0
Cash flows from financing activities:
Change in uncashed checks	0	0
Proceeds from exercise of stock options	30	39
Proceeds from employee stock purchase plan	1,238	699
Remittance of shares, net		(1,784)
Excess tax benefit of stock-based compensation	713	1,105
Deferred financing costs paid		(5,628)
Payments on capital leases	0	0
Distribution of cash earned on employee participation plan	(38)	0
Issuance of senior secured notes, including premium		261,250
Dividends (paid) / received	10,010	10,186
Interest (payments) / received	0	0
Net cash from financing activities	11,953	265,867
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(6,057)	268,765
Cash and cash equivalents, beginning of period	91,581	100,476
Cash and cash equivalents, end of period	85,524	369,241
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	10,827	3,937
Cash flows from investing activities:
Additions to property, plant and equipment	(14,678)	(14,884)
Proceeds from slales of fixed assets	146	67
Acquisitions, net of cash acquired	(2,276)	0
Costs to obtain or renew permits	(106)	(217)
Proceeds from sales of marketable securities		0
Purchase of available for sale securities	0
Other	603
Net cash used in investing activities	(16,311)	(15,034)
Cash flows from financing activities:
Change in uncashed checks	(7,125)	(2,087)
Proceeds from exercise of stock options	0	0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net		0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid		0
Payments on capital leases	(361)	(186)
Distribution of cash earned on employee participation plan	0	0
Issuance of senior secured notes, including premium		0
Dividends (paid) / received	(13,428)	(24,306)
Interest (payments) / received	16,783	24,132
Net cash from financing activities	(4,131)	(2,447)
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(9,615)	(13,544)
Cash and cash equivalents, beginning of period	128,071	124,582
Cash and cash equivalents, end of period	118,456	111,038
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	36,736	8,021
Cash flows from investing activities:
Additions to property, plant and equipment	(12,983)	(19,231)
Proceeds from slales of fixed assets	279	946
Acquisitions, net of cash acquired	(6,475)	(2,152)
Costs to obtain or renew permits	(319)	(105)
Proceeds from sales of marketable securities		388
Purchase of available for sale securities	(4,468)
Other	4,517
Net cash used in investing activities	(19,449)	(20,154)
Cash flows from financing activities:
Change in uncashed checks	(6,451)	(3,129)
Proceeds from exercise of stock options	0	0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net		0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid		0
Payments on capital leases	(1,805)	(1,504)
Distribution of cash earned on employee participation plan	0	(189)
Issuance of senior secured notes, including premium		0
Dividends (paid) / received	3,418	14,120
Interest (payments) / received	(16,783)	(24,132)
Net cash from financing activities	(21,621)	(14,834)
Effect of exchange rate change on cash	810	1,299
(Decrease) increase in cash and cash equivalents	(3,524)	(25,668)
Cash and cash equivalents, beginning of period	41,071	77,152
Cash and cash equivalents, end of period	$ 37,547	$ 51,484