GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 196,039	$ 280,114
Cash flows from investing activities:
Additions to property, plant and equipment	(198,877)	(207,641)
Proceeds from sales of fixed assets	5,913	3,700
Acquisitions, net of cash acquired	(6,150)	(59,458)
Costs to obtain or renew permits	(5,443)	(4,357)
Proceeds from sales of marketable securities	12,947	0
Other	914	(11)
Net cash used in investing activities	(190,696)	(267,767)
Cash flows from financing activities:
Change in uncashed checks	(591)	9,754
Proceeds from exercise of stock options	0	399
Proceeds from employee stock purchase plan	4,364	5,327
Remittance of shares, net	(2,668)	(599)
Repurchases of common stock	(48,329)	0
Excess tax benefit of stock-based compensation	829	1,589
Deferred financing costs paid	0	(2,446)
Payments on capital leases	(1,682)	(4,096)
Repayment of long-term obligations	(5,000)	0
Issuance costs related to 2012 issuance of common stock	0	(250)
Dividends (paid) / received	0	0
Interest received / (payments)	0	0
Net cash from financing activities	(53,077)	9,678
Effect of exchange rate change on cash	(4,318)	(3,226)
(Decrease) increase in cash and cash equivalents	(52,052)	18,799
Cash and cash equivalents, beginning of period	310,073	229,836
Cash and cash equivalents, end of period	258,021	248,635
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	50,804	(38,228)
Cash flows from investing activities:
Additions to property, plant and equipment	0	0
Proceeds from sales 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
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		399
Proceeds from employee stock purchase plan	4,364	5,327
Remittance of shares, net	(2,668)	(599)
Repurchases of common stock	(48,329)
Excess tax benefit of stock-based compensation	829	1,589
Deferred financing costs paid		(2,446)
Payments on capital leases	0	0
Repayment of long-term obligations	(5,000)
Issuance costs related to 2012 issuance of common stock		(250)
Dividends (paid) / received	0	0
Interest received / (payments)	0	0
Net cash from financing activities	(50,804)	4,020
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	0	(34,208)
Cash and cash equivalents, beginning of period	1,006	35,214
Cash and cash equivalents, end of period	1,006	1,006
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	42,595	176,844
Cash flows from investing activities:
Additions to property, plant and equipment	(133,335)	(101,813)
Proceeds from sales of fixed assets	3,635	819
Acquisitions, net of cash acquired	(6,150)	(59,458)
Costs to obtain or renew permits	(589)	(221)
Proceeds from sales of marketable securities	0
Other		0
Net cash used in investing activities	(136,439)	(160,673)
Cash flows from financing activities:
Change in uncashed checks	635	9,427
Proceeds from exercise of stock options		0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net	0	0
Repurchases of common stock	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid		0
Payments on capital leases	(130)	(178)
Repayment of long-term obligations	0
Issuance costs related to 2012 issuance of common stock		0
Dividends (paid) / received	(7,412)	(10,284)
Interest received / (payments)	29,833	32,107
Net cash from financing activities	22,926	31,072
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(70,918)	47,243
Cash and cash equivalents, beginning of period	235,445	140,683
Cash and cash equivalents, end of period	164,527	187,926
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	102,640	141,498
Cash flows from investing activities:
Additions to property, plant and equipment	(65,542)	(105,828)
Proceeds from sales of fixed assets	2,278	2,881
Acquisitions, net of cash acquired	0	0
Costs to obtain or renew permits	(4,854)	(4,136)
Proceeds from sales of marketable securities	12,947
Other		(11)
Net cash used in investing activities	(54,257)	(107,094)
Cash flows from financing activities:
Change in uncashed checks	(1,226)	327
Proceeds from exercise of stock options		0
Proceeds from employee stock purchase plan	0	0
Remittance of shares, net	0	0
Repurchases of common stock	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid		0
Payments on capital leases	(1,552)	(3,918)
Repayment of long-term obligations	0
Issuance costs related to 2012 issuance of common stock		0
Dividends (paid) / received	7,412	10,284
Interest received / (payments)	(29,833)	(32,107)
Net cash from financing activities	(25,199)	(25,414)
Effect of exchange rate change on cash	(4,318)	(3,226)
(Decrease) increase in cash and cash equivalents	18,866	5,764
Cash and cash equivalents, beginning of period	73,622	53,939
Cash and cash equivalents, end of period	$ 92,488	$ 59,703