Significant accounting policies - Additional Information (Detail)	12 Months Ended							0 Months Ended		0 Months Ended		3 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2013 Director [Member] Minimum [Member] CAD	Dec. 31, 2013 Director [Member] Maximum [Member] CAD	Dec. 31, 2013 Senior Executive [Member] Minimum [Member] USD ($)	Dec. 31, 2013 Senior Executive [Member] Maximum [Member] USD ($)	Dec. 30, 2013 Manitoulin Transport [Member] USD ($)	Dec. 09, 2013 Manitoulin Transport [Member] USD ($)	Dec. 30, 2013 TransForce [Member] USD ($)	Dec. 20, 2013 TransForce [Member] USD ($)	Sep. 30, 2013 U.S. LTL [Member] USD ($)
Accounting Policies [Line Items]
Cash paid per common share									$ 6.00		$ 6.50
Termination fee								$ 4,000,000		$ 4,000,000
Net allowance for doubtful accounts	400,000	400,000
Company's stock option outstanding	557,750	742,800	841,900
Term of option	10 years
Vesting period	5 years
Advertising costs	417,000	264,000	397,000
Impairment charge on long-lived assets												49,700,000
Deferred share unit, entitlement amount				35,000.00	60,000.00	$ 2,500.00	$ 20,000.00