Acquisitions (Narrative) (Detail) $ in Thousands	1 Months Ended						3 Months Ended	12 Months Ended
	Nov. 30, 2015 USD ($) territory property	Mar. 31, 2015 USD ($)	Jan. 31, 2015 USD ($) territory	Oct. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) entity	Dec. 31, 2014 USD ($) entity	Dec. 31, 2013 USD ($) entity
Business Acquisition [Line Items]
Cash consideration, net of cash acquired								$ 230,517	$ 126,181	$ 64,156
Debt assumed								111,324
Long-term note issued to former owners								815	42,538	40
Goodwill expected to be deductible for tax purposes								40,863	18,778	39,731
Trade receivables acquired in business combination gross contractual amount								13,037	3,981	414
Trade receivables acquired In business combination expected to be uncollectible amount								466	196	203
Acquisition related costs								$ 4,235	$ 2,147	$ 1,946
Number of individual businesses acquired that are not specifically described | entity								11	5	8
Payment of contingent consideration recorded at acquisition date								$ 2,190	$ 24,847	$ 23,941
Goodwill								$ 140,822	18,778	$ 39,901
Contingent consideration									$ 70,165
Fair value of acquired working capital is provisional | entity								4
Dunn & Company LLC [Member]
Business Acquisition [Line Items]
Contingent consideration payable period								2 years
Contingent consideration						$ 2,923
Dunn & Company LLC [Member] | Minimum [Member]
Business Acquisition [Line Items]
Fair value discount rate								2.40%
Dunn & Company LLC [Member] | Maximum [Member]
Business Acquisition [Line Items]
Fair value discount rate								2.70%
Contingent consideration						3,000
Screwbean Landfill, LLC [Member] | Dunn & Company LLC [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired						$ 27,020
Rumsey Environmental LLC [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired					$ 16,000
Fair value discount rate								2.80%
Contingent consideration payable period								2 years
Contingent consideration					1,891
Rumsey Environmental LLC [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration					$ 2,000
Section 18 [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired				$ 64,425
Fair value discount rate								5.20%
Decrease in contingent consideration							$ (20,642)
Payment of contingent consideration recorded at acquisition date								$ 2,000
Contingent consideration				$ 37,724
Section 18 [Member] | Minimum [Member]
Business Acquisition [Line Items]
Contingent consideration payable period								1 year
Section 18 [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration payable period								4 years
Shale Gas [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired			$ 41,000
Number of E&P waste stream treatment and recycling operations acquired | territory			2
Contingent consideration payable period								2 years
Contingent consideration								$ 0
DNCS [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired		$ 30,000
Long-term note issued to former owners		$ 5,088
Long-term note payment period								20 years
Fair value discount rate		4.75%
Total future cash payments		$ 7,500
DNCS [Member] | First 10 Years [Member]
Business Acquisition [Line Items]
Annual principal payment		500
DNCS [Member] | Years 11 Through 20 [Member]
Business Acquisition [Line Items]
Annual principal payment		$ 250
Rock River Environmental Services Inc [Member]
Business Acquisition [Line Items]
Cash consideration, net of cash acquired	$ 225,000
Number of counties that operations were acquired in | territory	19
Number of collection operations acquired | property	5
Number of landfills acquired | property	2
Number of compost facilities acquired | property	1
Number of transfer stations acquired | property	1
Number of recycling facilities acquired | property	1