Mergers and Acquisitions (Details) CAD in Millions, $ in Millions	3 Months Ended										6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 28, 2015 USD ($)	Mar. 29, 2015 CAD	Mar. 29, 2015 USD ($)	Sep. 28, 2014 USD ($)	Jun. 29, 2014 USD ($)	Mar. 30, 2014 USD ($)	Dec. 29, 2013 CAD	Dec. 29, 2013 USD ($)	Mar. 31, 2013 CAD	Mar. 31, 2013 USD ($)	Mar. 30, 2014 USD ($)	Jun. 28, 2015 USD ($)	Jun. 29, 2014 USD ($)	Sep. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)
Business acquisition
Contingent earn-out liability	$ 4.1											$ 4.1
Aggregate maximum of contingent consideration	$ 30.4											30.4
Earn-out paid to former owners												3.2	$ 20.6
Earn-outs paid to former owners reported as cash used in financing activities												3.2	18.7
Earn-outs paid to former owners reported as cash used in operating activities													1.9
Maximum
Business acquisition
Earn-out period for operating income projection	3 years
Minimum
Business acquisition
Earn-out period for operating income projection	2 years
CEG
Business acquisition
Aggregate fair value of purchase prices	$ 15.9
Cash paid to the sellers	11.8
Contingent earn-out liability	4.1											4.1
Aggregate maximum of contingent consideration	$ 9.8											9.8
Caber
Business acquisition
Contingent earn-out liability			$ 0.0
Aggregate maximum of contingent consideration | CAD							CAD 8.0
Earn-out period for operating income projection							2 years	2 years
Decreases (increase) in contingent earn-out liabilities				$ (1.0)								3.1
Gains on fair value adjustment in operating income												$ 3.1
Earn-out paid to former owners		CAD 4.0	3.2
Potential earn-out to be paid each year | CAD							CAD 4.0
Potential maximum earn-out to be paid | CAD							4.0
Minimum operating income threshold to earn contingent consideration during year one | CAD							4.0
Minimum operating income threshold to earn contingent consideration during year two | CAD							4.6
Operating income to earn maximum consideration during the first year | CAD							4.4
Operating income to earn maximum consideration during the second year | CAD							5.1
Initial fair value of the contingent consideration | CAD							CAD 6.5
Estimated potential earn-out (as a percent)							81.00%	81.00%
Gain (loss) on change in contingent consideration			$ 3.1	(1.0)
Parkland
Business acquisition
Contingent earn-out liability				0.0		$ 0.0					$ 0.0			$ 0.0	$ 0.0
Earn-out period for operating income projection									3 years	3 years
Net gains on fair value adjustments in operating income														44.6
Net decrease in contingent earn-out liabilities														$ 44.6
Potential maximum earn-out to be paid | CAD									CAD 56.0
Potential earn-out to be paid in the first year | CAD									12.0
Potential earn-out to be paid in the second year | CAD									22.0
Potential earn-out to be paid in the third year | CAD									22.0
Minimum operating income threshold to earn contingent consideration during year one | CAD									34.7
Minimum operating income threshold to earn contingent consideration during year two | CAD									38.2
Minimum operating income threshold to earn contingent consideration during year three | CAD									41.9
Operating income to earn maximum consideration during the first year | CAD									42.5
Operating income to earn maximum consideration during the second year | CAD									46.4
Operating income to earn maximum consideration during the third year | CAD									50.6
Initial fair value of the contingent consideration | CAD									CAD 46.8
Estimated potential earn-out (as a percent)									84.00%	84.00%
Gain (loss) on change in contingent consideration				$ 19.9		19.1		$ 5.6			$ 24.7
Profit previously recognized on project						5.3
AEG
Business acquisition
Amount recorded as liabilities in accordance with the purchase agreements										$ 21.5
Earn-out period for operating income projection									2 years	2 years
Contingent consideration liability										$ 27.1
Annual payment amount										11.3
One-time payment										4.5
Earn-out provision paid for meeting second earn out provision										4.5
Decreases (increase) in contingent earn-out liabilities					$ 8.9
Gains on fair value adjustment in operating income					8.9
Minimum operating income threshold to earn contingent consideration during year one										10.0
Minimum operating income threshold to earn contingent consideration during year two										11.0
Operating income to earn maximum consideration during the first year										17.5
Operating income to earn maximum consideration during the second year										$ 18.5
Estimated potential earn-out (as a percent)									79.00%	79.00%
Gain (loss) on change in contingent consideration					$ 8.9			$ 1.0
Minimum operating income in both years for earning one-time payment										$ 9.0
Earn-outs paid to former owners reported as cash used in financing activities						$ 9.1
AEG and Parkland
Business acquisition
Decreases (increase) in contingent earn-out liabilities													34.9
Gains on fair value adjustment in operating income													$ 34.9