Long-term debt - Long-Term Debt (Detail) In Thousands, unless otherwise specified	Dec. 31, 2013 USD ($)	Dec. 31, 2013 CAD	Dec. 31, 2012 USD ($)	Dec. 31, 2012 CAD	Dec. 31, 2013 Revolving credit facility [Member] USD ($)	Dec. 31, 2012 Revolving credit facility [Member] USD ($)	Dec. 31, 2013 Canadian Real Estate Facilities [Member] USD ($)	Dec. 31, 2012 Canadian Real Estate Facilities [Member] USD ($)
Debt Instrument [Line Items]
Long term debt						$ 8,500	$ 46,144	$ 50,495
Capital leases	5,953	6,300	1,307	1,300
Total	52,097		60,302
Less current portion	1,846		1,333
Long-term debt excluding current	$ 50,251		$ 58,969