GUARANTOR AND NON-GUARANTOR SUBSIDIARIES (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed consolidating statement of cash flows
Net cash from operating activities	$ 297,366	$ 415,839	$ 324,365
Cash flows from investing activities:
Additions to property, plant and equipment	(257,613)	(280,207)	(197,397)
Proceeds from sales of fixed assets	8,164	4,699	8,125
Proceeds from long-term investments	13,861
Acquisitions, net of cash acquired	(16,187)	(63,264)	(1,373,921)
Additions to intangible assets including costs to obtain or renew permits	(6,519)	(6,740)	(4,046)
Intercompany_Investing	0
Intercompany_debt_Investing	0	0	0
Purchase of marketable securities	0	0	(10,517)
Other	0	0	5,120
Net cash used in investing activities	(258,294)	(345,512)	(1,572,636)
Cash flows from financing activities:
Change in uncashed checks	15,069	12,268	(12,070)
Proceeds from exercise of stock options	0	400	288
Remittance of shares, net	(2,793)	(731)	(2,912)
Excess tax benefit of stock-based compensation	878	1,409	2,556
Deferred financing costs paid	0	(2,504)	(19,056)
Proceeds from employee stock purchase plan	4,364	7,425	6,196
Repurchases of common stock	(104,341)	0	0
Payments on capital leases	(2,122)	(4,891)	(6,599)
Proceeds from issuance of common stock, net	0	0	369,520
Repayment of long-term obligations	(5,000)	0	(520,000)
Distribution of cash earned on employee participation plan	0	0	(55)
Issuance of senior secured notes, including premium			1,400,000
Issuance costs related to issuances of common stock	0	(250)	0
Dividends paid	0	0	0
Net cash (used in) from financing activities	(93,945)	13,126	1,217,868
Intercompany_Financing	0
Effect of exchange rate change on cash	(8,321)	(3,216)	(484)
(Decrease) increase in cash and cash equivalents	(63,194)	80,237	(30,887)
Cash and cash equivalents, beginning of year	310,073	229,836	260,723
Cash and cash equivalents, end of year	246,879	310,073	229,836
Intercompany_debt_Financing	0	0	0
Clean Harbors, Inc.
Condensed consolidating statement of cash flows
Net cash from operating activities	(5,242)	(33,932)	(35,645)
Cash flows from investing activities:
Additions to property, plant and equipment	0	0	0
Proceeds from sales of fixed assets	0	0	0
Proceeds from long-term investments	0
Acquisitions, net of cash acquired	0	(6,025)	(1,257,259)
Additions to intangible assets including costs to obtain or renew permits	0	0	0
Intercompany_Investing	0
Intercompany_debt_Investing	0	0	0
Purchase of marketable securities			0
Other			0
Net cash used in investing activities	0	(6,025)	(1,257,259)
Cash flows from financing activities:
Change in uncashed checks	0	0	0
Proceeds from exercise of stock options		400	288
Remittance of shares, net	(2,793)	(731)	(2,912)
Excess tax benefit of stock-based compensation	878	1,409	2,556
Deferred financing costs paid		(2,504)	(19,056)
Proceeds from employee stock purchase plan	4,364	7,425	6,196
Repurchases of common stock	(104,341)
Payments on capital leases	0	0	0
Proceeds from issuance of common stock, net			369,520
Repayment of long-term obligations	(5,000)		(520,000)
Distribution of cash earned on employee participation plan			(55)
Issuance of senior secured notes, including premium			1,400,000
Issuance costs related to issuances of common stock		(250)
Dividends paid	0	0	0
Net cash (used in) from financing activities	5,242	5,749	1,236,537
Intercompany_Financing	112,134
Effect of exchange rate change on cash	0	0	0
(Decrease) increase in cash and cash equivalents	0	(34,208)	(56,367)
Cash and cash equivalents, beginning of year	1,006	35,214	91,581
Cash and cash equivalents, end of year	1,006	1,006	35,214
Intercompany_debt_Financing	0	0	0
U.S. Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	70,761	277,445	246,774
Cash flows from investing activities:
Additions to property, plant and equipment	(172,525)	(145,075)	(117,286)
Proceeds from sales of fixed assets	3,956	1,078	3,810
Proceeds from long-term investments	0
Acquisitions, net of cash acquired	(6,550)	(57,239)	(63,351)
Additions to intangible assets including costs to obtain or renew permits	(623)	(5,247)	(712)
Intercompany_Investing	(112,134)
Intercompany_debt_Investing	143,467	27,525	(25,697)
Purchase of marketable securities			0
Other			500
Net cash used in investing activities	(144,409)	(178,958)	(202,736)
Cash flows from financing activities:
Change in uncashed checks	11,046	9,922	(6,761)
Proceeds from exercise of stock options		0	0
Remittance of shares, net	0	0	0
Excess tax benefit of stock-based compensation	0	0	0
Deferred financing costs paid		0	0
Proceeds from employee stock purchase plan	0	0	0
Repurchases of common stock	0
Payments on capital leases	(170)	(227)	(850)
Proceeds from issuance of common stock, net			0
Repayment of long-term obligations	0		0
Distribution of cash earned on employee participation plan			0
Issuance of senior secured notes, including premium			0
Issuance costs related to issuances of common stock		0
Dividends paid	(18,586)	(13,360)	(23,815)
Net cash (used in) from financing activities	(7,710)	(3,665)	(31,426)
Intercompany_Financing	0
Effect of exchange rate change on cash	0	0	0
(Decrease) increase in cash and cash equivalents	(81,358)	94,822	12,612
Cash and cash equivalents, beginning of year	235,505	140,683	128,071
Cash and cash equivalents, end of year	154,147	235,505	140,683
Intercompany_debt_Financing	0	0	0
Foreign Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from operating activities	250,433	185,686	137,051
Cash flows from investing activities:
Additions to property, plant and equipment	(85,088)	(135,132)	(80,111)
Proceeds from sales of fixed assets	4,208	3,621	4,315
Proceeds from long-term investments	13,861
Acquisitions, net of cash acquired	(9,637)	0	(53,311)
Additions to intangible assets including costs to obtain or renew permits	(5,896)	(1,493)	(3,334)
Intercompany_Investing	0
Intercompany_debt_Investing	0	0	0
Purchase of marketable securities			(10,517)
Other			4,620
Net cash used in investing activities	(82,552)	(133,004)	(138,338)
Cash flows from financing activities:
Change in uncashed checks	4,023	2,346	(5,309)
Proceeds from exercise of stock options		0	0
Remittance of shares, net	0	0	0
Excess tax benefit of stock-based compensation	0	0	0
Deferred financing costs paid		0	0
Proceeds from employee stock purchase plan	0	0	0
Repurchases of common stock	0
Payments on capital leases	(1,952)	(4,664)	(5,749)
Proceeds from issuance of common stock, net			0
Repayment of long-term obligations	0		0
Distribution of cash earned on employee participation plan			0
Issuance of senior secured notes, including premium			0
Issuance costs related to issuances of common stock		0
Dividends paid	0	0	0
Net cash (used in) from financing activities	(141,396)	(29,843)	14,639
Intercompany_Financing	0
Effect of exchange rate change on cash	(8,321)	(3,216)	(484)
(Decrease) increase in cash and cash equivalents	18,164	19,623	12,868
Cash and cash equivalents, beginning of year	73,562	53,939	41,071
Cash and cash equivalents, end of year	91,726	73,562	53,939
Intercompany_debt_Financing	(143,467)	(27,525)	25,697
Consolidating Adjustments
Condensed consolidating statement of cash flows
Net cash from operating activities	(18,586)	(13,360)	(23,815)
Cash flows from investing activities:
Additions to property, plant and equipment	0	0	0
Proceeds from sales of fixed assets	0	0	0
Proceeds from long-term investments	0
Acquisitions, net of cash acquired	0	0	0
Additions to intangible assets including costs to obtain or renew permits	0	0	0
Intercompany_Investing	112,134
Intercompany_debt_Investing	(143,467)	(27,525)	25,697
Purchase of marketable securities			0
Other			0
Net cash used in investing activities	(31,333)	(27,525)	25,697
Cash flows from financing activities:
Change in uncashed checks	0	0	0
Proceeds from exercise of stock options		0	0
Remittance of shares, net	0	0	0
Excess tax benefit of stock-based compensation	0	0	0
Deferred financing costs paid		0	0
Proceeds from employee stock purchase plan	0	0	0
Repurchases of common stock	0
Payments on capital leases	0	0	0
Proceeds from issuance of common stock, net			0
Repayment of long-term obligations	0		0
Distribution of cash earned on employee participation plan			0
Issuance of senior secured notes, including premium			0
Issuance costs related to issuances of common stock		0
Dividends paid	18,586	13,360	23,815
Net cash (used in) from financing activities	49,919	40,885	(1,882)
Intercompany_Financing	(112,134)
Effect of exchange rate change on cash	0	0	0
(Decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents, beginning of year	0	0	0
Cash and cash equivalents, end of year	0	0	0
Intercompany_debt_Financing	$ 143,467	$ 27,525	$ (25,697)