GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	$ 120,051	$ 193,815
Cash flows used in investing activities:
Additions to property, plant and equipment	(123,529)	(124,145)
Proceeds from sales of fixed assets	2,668	2,646
Acquisitions, net of cash acquired	(58,989)	(79,610)
Costs to obtain or renew permits	(973)	(3,088)
Purchases of available-for-sale securities	(598)	0
Investment in subsidiaries	0
Intercompany	0	0
Net cash used in investing activities	(181,421)	(204,197)
Cash flows from (used in) financing activities:
Change in uncashed checks	(11,022)	(22,160)
Exercise of stock options	184	397
Issuance of restricted shares, net of shares remitted	(1,879)	(1,837)
Repurchases of common stock	(10,134)	(32,203)
Excess tax benefit of stock-based compensation	2	102
Deferred financing costs paid	(2,614)	0
Payments of capital leases	0	(471)
Issuance of senior secured notes, including premium	250,625
Intercompany	0	0
Net cash from (used in) financing activities	225,162	(56,172)
Effect of exchange rate change on cash	4,423	(6,704)
Increase (decrease) in cash and cash equivalents	168,215	(73,258)
Cash and cash equivalents, beginning of period	184,708	246,879
Cash and cash equivalents, end of period	352,923	173,621
Consolidating Adjustments
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	0	0
Cash flows used in 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
Purchases of available-for-sale securities	0
Investment in subsidiaries	250,625
Intercompany	11,827	31,830
Net cash used in investing activities	262,452	31,830
Cash flows from (used in) financing activities:
Change in uncashed checks	0	0
Exercise of stock options	0	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
Deferred financing costs paid	0
Payments of capital leases		0
Issuance of senior secured notes, including premium	(250,625)
Intercompany	(11,827)	(31,830)
Net cash from (used in) financing activities	(262,452)	(31,830)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Clean Harbors, Inc. | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	42,990	4,913
Cash flows used in 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
Purchases of available-for-sale securities	(102)
Investment in subsidiaries	(250,625)
Intercompany	0	0
Net cash used in investing activities	(250,727)	0
Cash flows from (used in) financing activities:
Change in uncashed checks	0	0
Exercise of stock options	184	397
Issuance of restricted shares, net of shares remitted	(1,879)	(1,837)
Repurchases of common stock	(10,134)	(32,203)
Excess tax benefit of stock-based compensation	2	102
Deferred financing costs paid	(2,614)
Payments of capital leases		0
Issuance of senior secured notes, including premium	250,625
Intercompany	11,827	31,830
Net cash from (used in) financing activities	248,011	(1,711)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	40,274	3,202
Cash and cash equivalents, beginning of period	11,017	1,006
Cash and cash equivalents, end of period	51,291	4,208
U.S. Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	65,860	158,241
Cash flows used in investing activities:
Additions to property, plant and equipment	(105,175)	(104,068)
Proceeds from sales of fixed assets	694	368
Acquisitions, net of cash acquired	(48,989)	(79,610)
Costs to obtain or renew permits	(908)	(4)
Purchases of available-for-sale securities	0
Investment in subsidiaries	0
Intercompany	(11,827)	(31,830)
Net cash used in investing activities	(166,205)	(215,144)
Cash flows from (used in) financing activities:
Change in uncashed checks	(9,266)	(16,474)
Exercise of stock options	0	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
Deferred financing costs paid	0
Payments of capital leases		(193)
Issuance of senior secured notes, including premium	250,625
Intercompany	0	0
Net cash from (used in) financing activities	241,359	(16,667)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	141,014	(73,570)
Cash and cash equivalents, beginning of period	83,479	154,147
Cash and cash equivalents, end of period	224,493	80,577
Foreign Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	11,201	30,661
Cash flows used in investing activities:
Additions to property, plant and equipment	(18,354)	(20,077)
Proceeds from sales of fixed assets	1,974	2,278
Acquisitions, net of cash acquired	(10,000)	0
Costs to obtain or renew permits	(65)	(3,084)
Purchases of available-for-sale securities	(496)
Investment in subsidiaries	0
Intercompany	0	0
Net cash used in investing activities	(26,941)	(20,883)
Cash flows from (used in) financing activities:
Change in uncashed checks	(1,756)	(5,686)
Exercise of stock options	0	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
Deferred financing costs paid	0
Payments of capital leases		(278)
Issuance of senior secured notes, including premium	0
Intercompany	0	0
Net cash from (used in) financing activities	(1,756)	(5,964)
Effect of exchange rate change on cash	4,423	(6,704)
Increase (decrease) in cash and cash equivalents	(13,073)	(2,890)
Cash and cash equivalents, beginning of period	90,212	91,726
Cash and cash equivalents, end of period	$ 77,139	$ 88,836