Acquisitions (Narrative) (Detail) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) entity	Jun. 30, 2017 USD ($) entity	Jun. 30, 2018 USD ($) entity	Dec. 31, 2016 USD ($) customer	Jan. 31, 2017 territory
Business Acquisition [Line Items]
Acquisition-related costs			$ 4,584	$ 2,459
Number of individual businesses acquired that are not specifically described | entity				6
Number of immaterial businesses acquired in period | entity			12
Revenues	$ 1,239,968	$ 1,175,569	$ 2,380,099	$ 2,266,835
Goodwill expected to be deductible for tax purposes	165,465	11,111	165,465	11,111	$ 165,465
Trade receivables acquired in business combination gross contractual amount	12,806	13,964	12,806	13,964	12,806
Trade receivables acquired in business combination expected to be uncollectible amount	572	$ 700	$ 572	$ 700	$ 572
Fair value of acquired working capital is provisional | entity					8
Groot Industries, Inc. [Member]
Business Acquisition [Line Items]
Revenues						$ 200,000
Groot Industries, Inc. [Member]
Business Acquisition [Line Items]
Number of customers served by company acquired | customer						300,000
Number of collection operations acquired | territory							7
Number of transfer stations acquired | territory							6
Number of recycling facilities acquired | territory							1
One Acquisition [Member]
Business Acquisition [Line Items]
Contingent consideration payable period			3 years
Fair value discount rate			2.70%
Contingent consideration	11,593		$ 11,593		$ 11,593
One Acquisition [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration	$ 12,582		$ 12,582		$ 12,582