CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 147,455	$ 133,802
Operating expenses:
Cost of operations	105,610	94,544
General and administration	21,027	18,845
Depreciation and amortization	15,983	13,849
Contract settlement charge	2,100	0
Southbridge Landfill closure charge	1,586	0
Development project charge	311	0
Total operating expenses	146,617	127,238
Operating income	838	6,564
Other expense (income):
Interest income	(29)	(69)
Interest expense	6,454	6,450
Loss on debt extinguishment	0	472
Other income	(89)	(81)
Other expense, net	6,336	6,772
Loss before income taxes	(5,498)	(208)
(Benefit) provision for income taxes	(1,588)	16
Net loss	$ (3,910)	$ (224)
Basic and diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding (in shares)	42,370	41,584
Basic and diluted earnings per common share (in dollars per share)	$ (0.09)	$ (0.01)