GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed consolidating statement of cash flows
Net cash from operating activities		$ 309,593	$ 196,039
Cash flows from investing activities:
Additions to property, plant and equipment		(189,999)	(198,877)
Proceeds from sales of fixed assets		3,740	5,913
Acquisitions, net of cash acquired		(79,610)	(6,150)
Costs to obtain or renew permits		(4,633)	(5,443)
Proceeds from sale of long term investments			12,947
Intercompany		0	0
Proceeds from Insurance Settlement	$ 914
Net cash used in investing activities		(270,502)	(190,696)
Cash flows from financing activities:
Change in uncashed checks		(21,882)	(591)
Proceeds from exercise of stock options		397	0
Proceeds from employee stock purchase plan		0	4,364
Issuance of restricted shares, net of shares remitted		(2,027)	(2,668)
Repurchases of common stock		(69,155)	(48,329)
Excess tax benefit of stock-based compensation		102	829
Repayment of long-term obligations		0	(5,000)
Payments on capital leases		(500)	(1,682)
Dividends paid			0
Intercompany		0	0
Net cash from financing activities		(93,065)	(53,077)
Effect of exchange rate change on cash		(13,714)	(4,318)
Decrease in cash and cash equivalents		(67,688)	(52,052)
Cash and cash equivalents, beginning of period		246,879	310,073
Cash and cash equivalents, end of period	258,021	179,191	258,021
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities		9,503	(5,193)
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 sale of long term investments			0
Intercompany		0	0
Proceeds from Insurance Settlement			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		397
Proceeds from employee stock purchase plan			4,364
Issuance of restricted shares, net of shares remitted		(2,027)	(2,668)
Repurchases of common stock		(69,155)	(48,329)
Excess tax benefit of stock-based compensation		102	829
Repayment of long-term obligations			(5,000)
Payments on capital leases		0	0
Dividends paid			0
Intercompany		71,182	55,997
Net cash from financing activities		499	5,193
Effect of exchange rate change on cash		0	0
Decrease in cash and cash equivalents		10,002	0
Cash and cash equivalents, beginning of period		1,006	1,006
Cash and cash equivalents, end of period	1,006	11,008	1,006
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities		240,713	139,640
Cash flows from investing activities:
Additions to property, plant and equipment		(162,329)	(133,320)
Proceeds from sales of fixed assets		1,177	3,634
Acquisitions, net of cash acquired		(79,610)	(6,150)
Costs to obtain or renew permits		(4)	(589)
Proceeds from sale of long term investments			0
Intercompany		(71,182)	(55,997)
Proceeds from Insurance Settlement			0
Net cash used in investing activities		(311,948)	(192,422)
Cash flows from financing activities:
Change in uncashed checks		(16,635)	579
Proceeds from exercise of stock options		0
Proceeds from employee stock purchase plan			0
Issuance of restricted shares, net of shares remitted		0	0
Repurchases of common stock		0	0
Excess tax benefit of stock-based compensation		0	0
Repayment of long-term obligations			0
Payments on capital leases		(203)	(129)
Dividends paid			(18,586)
Intercompany		0	0
Net cash from financing activities		(16,838)	(18,136)
Effect of exchange rate change on cash		0	0
Decrease in cash and cash equivalents		(88,073)	(70,918)
Cash and cash equivalents, beginning of period		154,147	235,445
Cash and cash equivalents, end of period	164,527	66,074	164,527
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities		59,377	80,178
Cash flows from investing activities:
Additions to property, plant and equipment		(27,670)	(65,557)
Proceeds from sales of fixed assets		2,563	2,279
Acquisitions, net of cash acquired		0	0
Costs to obtain or renew permits		$ (4,629)	(4,854)
Proceeds from sale of long term investments			12,947
Intercompany			0
Proceeds from Insurance Settlement			914
Net cash used in investing activities		$ (29,736)	(54,271)
Cash flows from financing activities:
Change in uncashed checks		(5,247)	(1,170)
Proceeds from exercise of stock options		0
Proceeds from employee stock purchase plan			0
Issuance of restricted shares, net of shares remitted		0	0
Repurchases of common stock		0	0
Excess tax benefit of stock-based compensation		0	0
Repayment of long-term obligations			0
Payments on capital leases		(297)	(1,553)
Dividends paid			0
Intercompany		0	0
Net cash from financing activities		(5,544)	(2,723)
Effect of exchange rate change on cash		(13,714)	(4,318)
Decrease in cash and cash equivalents		10,383	18,866
Cash and cash equivalents, beginning of period		91,726	73,622
Cash and cash equivalents, end of period	$ 92,488	102,109	92,488
Consolidating Adjustments
Condensed consolidating statement of cash flows
Net cash from operating activities			(18,586)
Cash flows from investing activities:
Intercompany		(71,182)	55,997
Net cash used in investing activities		71,182	55,997
Cash flows from financing activities:
Dividends paid			18,586
Intercompany		(71,182)	(55,997)
Net cash from financing activities		$ (71,182)	$ (37,411)