Segment Reporting - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Inter-company revenues	$ 143,714	$ 137,279	$ 260,292	$ 250,476
Depreciation and amortization	16,241	17,167	29,990	30,775
Operating income (loss)	11,342	(473)	14,468	(4,147)
Total assets	657,528	657,425	657,528	657,425	$ 669,795
Eastern Region [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	43,822	39,674	77,090	71,012
Depreciation and amortization	6,752	6,903	11,990	12,231
Operating income (loss)	3,186	937	2,700	(3,922)
Total assets	207,507	204,711	207,507	204,711
Western Region [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	61,686	59,246	111,043	107,986
Depreciation and amortization	7,674	8,564	14,412	15,089
Operating income (loss)	7,684	(1,441)	12,679	1,162
Total assets	323,746	331,175	323,746	331,175
Recycling [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	11,462	11,979	21,756	22,340
Depreciation and amortization	1,110	1,067	2,226	2,133
Operating income (loss)	(401)	(131)	(2,411)	(1,615)
Total assets	50,457	49,570	50,457	49,570
Other [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	26,744	26,380	50,403	49,138
Depreciation and amortization	705	633	1,362	1,322
Operating income (loss)	873	162	1,500	228
Total assets	75,818	71,969	75,818	71,969
Intersubsegment Eliminations [Member] \| Inter-Company Revenue [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	(30,428)	(31,014)	(53,066)	(55,427)
Intersubsegment Eliminations [Member] \| Eastern Region [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	11,401	11,607	19,417	20,195
Intersubsegment Eliminations [Member] \| Western Region [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	18,504	18,863	32,901	34,247
Intersubsegment Eliminations [Member] \| Recycling [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	253	(58)	257	(121)
Intersubsegment Eliminations [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Inter-company revenues	$ 270	$ 602	$ 491	$ 1,106

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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