SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 151,133	$ 146,185	$ 421,236	$ 406,476
Depreciation and amortization	16,175	16,385	46,430	46,374
Operating income (loss)	17,378	12,696	34,947	27,164
Total assets	635,255	643,455	635,255	643,455	$ 633,669
Operating Segments
Segment Reporting Information [Line Items]
Revenues			421,236	406,476
Operating Segments | Eastern Region
Segment Reporting Information [Line Items]
Revenues	47,238	46,143	131,630	123,233
Depreciation and amortization	7,291	6,956	20,618	18,946
Operating income (loss)	4,452	4,523	6,742	7,224
Total assets	206,177	210,292	206,177	210,292
Operating Segments | Western Region
Segment Reporting Information [Line Items]
Revenues	63,171	62,387	175,093	173,429
Depreciation and amortization	7,010	7,617	20,409	22,029
Operating income (loss)	11,392	7,792	24,561	20,471
Total assets	326,862	323,915	326,862	323,915
Operating Segments | Recycling
Segment Reporting Information [Line Items]
Revenues	14,412	12,700	37,865	34,456
Depreciation and amortization	1,055	1,130	3,187	3,356
Operating income (loss)	1,529	277	923	(2,134)
Total assets	48,531	50,038	48,531	50,038
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues	26,312	24,955	76,648	75,358
Depreciation and amortization	819	682	2,216	2,043
Operating income (loss)	5	104	2,721	1,603
Total assets	53,685	59,209	53,685	59,209
Inter-company revenue
Segment Reporting Information [Line Items]
Revenues	(31,959)	(31,385)	(87,542)	(84,452)
Total assets		0		0
Inter-company revenue | Eastern Region
Segment Reporting Information [Line Items]
Revenues	12,775	12,531	34,003	31,948
Inter-company revenue | Western Region
Segment Reporting Information [Line Items]
Revenues	18,560	18,236	51,300	51,138
Inter-company revenue | Recycling
Segment Reporting Information [Line Items]
Revenues	94	318	1,026	575
Inter-company revenue | Other
Segment Reporting Information [Line Items]
Revenues	$ 530	$ 300	$ 1,213	$ 791