GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 114,944	$ 137,612
Cash flows from investing activities:
Additions to property, plant and equipment	(138,186)	(141,466)
Proceeds from sales of fixed assets	2,986	2,194
Acquisitions, net of cash acquired	(6,150)	0
Costs to obtain or renew permits	(2,891)	(2,169)
Proceeds from sales of marketable securities	12,947	0
Net cash used in investing activities	(131,294)	(141,441)
Cash flows from financing activities:
Change in uncashed checks	3,162	40,356
Proceeds from exercise of stock options	0	399
Proceeds from employee stock purchase plan	4,364	3,391
Remittance of shares, net	(2,215)	(169)
Repurchases of common stock	(14,657)	0
Excess tax benefit of stock-based compensation	644	1,326
Deferred financing costs paid	0	(2,446)
Payments on capital leases	(1,190)	(2,588)
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	(14,892)	40,019
Effect of exchange rate change on cash	(187)	(2,548)
(Decrease) increase in cash and cash equivalents	(31,429)	33,642
Cash and cash equivalents, beginning of period	310,073	229,836
Cash and cash equivalents, end of period	278,644	263,478
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	16,864	(36,459)
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
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	3,391
Remittance of shares, net	(2,215)	(169)
Repurchases of common stock	(14,657)
Excess tax benefit of stock-based compensation	644	1,326
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	(16,864)	2,251
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	35,046	84,226
Cash flows from investing activities:
Additions to property, plant and equipment	(90,515)	(62,818)
Proceeds from sales of fixed assets	1,015	803
Acquisitions, net of cash acquired	(6,150)	0
Costs to obtain or renew permits	(477)	(212)
Proceeds from sales of marketable securities	0
Net cash used in investing activities	(96,127)	(62,227)
Cash flows from financing activities:
Change in uncashed checks	4,595	37,118
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	(87)	(164)
Repayment of long-term obligations	0
Issuance costs related to 2012 issuance of common stock		0
Dividends (paid) / received	(7,412)	(6,989)
Interest received / (payments)	22,361	21,780
Net cash from financing activities	19,457	51,745
Effect of exchange rate change on cash	0	0
(Decrease) increase in cash and cash equivalents	(41,624)	73,744
Cash and cash equivalents, beginning of period	235,445	140,683
Cash and cash equivalents, end of period	193,821	214,427
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	63,034	89,845
Cash flows from investing activities:
Additions to property, plant and equipment	(47,671)	(78,648)
Proceeds from sales of fixed assets	1,971	1,391
Acquisitions, net of cash acquired	0	0
Costs to obtain or renew permits	(2,414)	(1,957)
Proceeds from sales of marketable securities	12,947
Net cash used in investing activities	(35,167)	(79,214)
Cash flows from financing activities:
Change in uncashed checks	(1,433)	3,238
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	(1,103)	(2,424)
Repayment of long-term obligations	0
Issuance costs related to 2012 issuance of common stock		0
Dividends (paid) / received	7,412	6,989
Interest received / (payments)	(22,361)	(21,780)
Net cash from financing activities	(17,485)	(13,977)
Effect of exchange rate change on cash	(187)	(2,548)
(Decrease) increase in cash and cash equivalents	10,195	(5,894)
Cash and cash equivalents, beginning of period	73,622	53,939
Cash and cash equivalents, end of period	$ 83,817	$ 48,045