Long term debt - Schedule of Long Term Debt (Details) - CAD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	$ 331,957	$ 295,958
Unamortized deferred financing costs	(3,896)	(1,773)
Less: current portion of long-term debt	(18,514)	(29,996)
Long-term portion of debt	313,443	265,962
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	18,600
2021	194,000
2022	4,100
2023	4,300
2024	41,300
Credit facilities
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	190,000	194,918
Convertible debentures
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	94,031	39,976
Mortgages
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	21,739	19,900
Promissory notes
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	14,648	42,937
Financing obligations
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term debt, gross	$ 15,435	$ 0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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