Net Income Per Share Information (Basic and Diluted Net Income Per Common Share) (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income attributable to Waste Connections for basic and diluted earnings per share	$ 60,762	$ 60,084	$ 62,664	$ 49,015	$ 49,426	$ 60,706	$ 43,967	$ 41,556	$ 232,525	$ 195,655	$ 159,093
Denominator:
Basic shares outstanding									124,215,346	123,597,540	121,172,381
Dilutive effect of stock options and warrants									90,334	186,006	308,681
Dilutive effect of restricted stock units									481,741	381,506	343,287
Diluted shares outstanding									124,787,421	124,165,052	121,824,349