Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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Pending Acquisition - Schedule of Derivatives (Details) CAD in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 23, 2017 USD ($)	Sep. 24, 2016 USD ($)	Sep. 23, 2017 USD ($)	Sep. 24, 2016 USD ($)	Sep. 23, 2017 CAD	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CAD
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) for the periods	$ 14,087	$ 0	$ 16,149	$ 0
Derivatives Not Designated as Hedging Instruments \| Foreign currency collar
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount \| CAD					CAD 300,000		CAD 0
Derivative Assets - fair value	16,163		16,163			$ 0
Derivative Liabilities - fair value	(14)		(14)			0
Derivatives Not Designated as Hedging Instruments \| Foreign currency collar \| Other non-operating income
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) for the periods		$ 0		$ 0
Derivatives Not Designated as Hedging Instruments \| Foreign currency collar \| Other current assets
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, total	$ 16,149		$ 16,149			$ 0