OPERATING SEGMENTS (Details) (USD $)	3 Months Ended
	Mar. 31, 2013 segment	Mar. 31, 2012	Dec. 31, 2012
OPERATING SEGMENTS
Number of reportable segments	2
OPERATING SEGMENTS
Revenue	$ 42,899,000	$ 33,013,000
Direct operating costs	21,084,000	17,638,000
Transportation costs	6,433,000	3,299,000
Gross profit	15,382,000	12,076,000
Selling, general & administrative expenses	5,726,000	5,605,000
Operating income	9,656,000	6,471,000
Interest income (expense), net	(216,000)	(219,000)
Foreign currency gain (loss)	(938,000)	1,091,000
Other income	97,000	80,000
Income before income taxes	8,599,000	7,423,000
Income tax expense	3,193,000	2,900,000
Net income	5,406,000	4,523,000
Depreciation, amortization & accretion	4,113,000	3,908,000
Capital expenditures	6,752,000	2,386,000
Total assets	219,946,000	197,727,000	218,694,000
Treatment and disposal
OPERATING SEGMENTS
Revenue	36,344,000	29,949,000
Transportation services
OPERATING SEGMENTS
Revenue	6,555,000	3,064,000
Operating Disposal Facilities
OPERATING SEGMENTS
Revenue	42,895,000	33,009,000
Direct operating costs	21,031,000	17,583,000
Transportation costs	6,433,000	3,299,000
Gross profit	15,431,000	12,127,000
Selling, general & administrative expenses	2,646,000	2,521,000
Operating income	12,785,000	9,606,000
Interest income (expense), net	4,000	5,000
Foreign currency gain (loss)	112,000	(99,000)
Other income	95,000	80,000
Income before income taxes	12,996,000	9,592,000
Net income	12,996,000	9,592,000
Depreciation, amortization & accretion	4,051,000	3,844,000
Capital expenditures	6,726,000	2,360,000
Total assets	211,620,000	188,646,000
Operating Disposal Facilities | Treatment and disposal
OPERATING SEGMENTS
Revenue	36,340,000	29,945,000
Operating Disposal Facilities | Transportation services
OPERATING SEGMENTS
Revenue	6,555,000	3,064,000
Non-Operating Disposal Facilities
OPERATING SEGMENTS
Revenue	4,000	4,000
Direct operating costs	53,000	55,000
Gross profit	(49,000)	(51,000)
Operating income	(49,000)	(51,000)
Other income	2,000
Income before income taxes	(47,000)	(51,000)
Net income	(47,000)	(51,000)
Depreciation, amortization & accretion	52,000	54,000
Capital expenditures		17,000
Total assets	86,000	95,000
Non-Operating Disposal Facilities | Treatment and disposal
OPERATING SEGMENTS
Revenue	4,000	4,000
Corporate
OPERATING SEGMENTS
Selling, general & administrative expenses	3,080,000	3,084,000
Operating income	(3,080,000)	(3,084,000)
Interest income (expense), net	(220,000)	(224,000)
Foreign currency gain (loss)	(1,050,000)	1,190,000
Income before income taxes	(4,350,000)	(2,118,000)
Income tax expense	3,193,000	2,900,000
Net income	(7,543,000)	(5,018,000)
Depreciation, amortization & accretion	10,000	10,000
Capital expenditures	26,000	9,000
Total assets	$ 8,240,000	$ 8,986,000