Net Income Per Share Information (Basic and Diluted Net Income Per Common Share) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income attributable to Waste Connections for basic and diluted earnings per share	$ 158,049	$ 159,109	$ 74,012	$ 433,579
Denominator:
Basic shares outstanding	262,998,317	263,853,681	263,253,087	263,768,258
Dilutive effect of equity-based awards	509,169	733,775	464,914	705,087
Diluted shares outstanding	263,507,486	264,587,456	263,718,001	264,473,345