Mergers and Acquisitions (Details) $ in Thousands, CAD in Millions	1 Months Ended	3 Months Ended											6 Months Ended	12 Months Ended
	Oct. 31, 2015 USD ($)	Jun. 28, 2015 USD ($)	Mar. 29, 2015 CAD	Mar. 29, 2015 USD ($)	Sep. 28, 2014 CAD	Sep. 28, 2014 USD ($)	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 ($)	Sep. 27, 2015 USD ($)	Sep. 28, 2014 USD ($)	Sep. 29, 2013 USD ($)	Oct. 31, 2015 AUD / shares	Sep. 27, 2015 USD ($)	Dec. 29, 2013 USD ($)	Sep. 29, 2013 USD ($)
Business acquisition
Aggregate maximum of contingent consideration																		$ 29,300
Contingent earn-out liability																		4,200
Estimated contingent earn-out liabilities
Beginning balance (at fair value)										$ 81,789			$ 81,789	$ 7,030	$ 81,789	$ 51,539
Estimated earn-out liabilities for acquisition during the fiscal year														4,100	6,242	75,253
Increases due to re-measurement of fair value reported in interest expense														136	1,846	2,433
Decreases (increase) in contingent earn-out liabilities														(3,113)	(58,694)	(9,560)
Foreign exchange impact														(785)	(3,507)	(2,480)
Earn-out payments
Reported as cash used in operating activities															(1,984)	(695)
Reported as cash used in investing activities																(1,279)
Reported as cash used in financing activities														(3,199)	(18,662)	(33,672)
Contingent consideration liability						$ 7,030				$ 81,789			81,789	$ 7,030	81,789	51,539		$ 4,169		$ 81,789
Maximum
Business acquisition
Period for contingent earn-out payments														3 years
Minimum
Business acquisition
Period for contingent earn-out payments														2 years
AEG, Parkland and other 2013 acquisitions
Business acquisition
Aggregate fair value of purchase prices																248,900
Cash paid to the sellers																171,600
Aggregate maximum of contingent consideration																				86,700
Contingent earn-out liability																				75,300
Liabilities																				$ 2,000
Prior to 2010 acquisitions
Estimated contingent earn-out liabilities
Estimated earn-out liabilities for acquisition during the fiscal year																250
CEG
Business acquisition
Aggregate fair value of purchase prices		$ 15,900
Cash paid to the sellers		11,800
Aggregate maximum of contingent consideration		9,800
Contingent earn-out liability		$ 4,100
Coffey | BIA | Subsequent Event | Forecast
Business acquisition
Ownership interest acquired																	100.00%
Cash to be paid per share (in AUD per Share) | AUD / shares																	AUD 0.425
Minimum percentage of ownership interest to be acquired																	90.00%
Aggregate fair value of purchase prices	$ 76,000
Caber
Business acquisition
Aggregate maximum of contingent consideration | CAD									CAD 8.0
Earn-out period for operating income projection									2 years	2 years
Gains on fair value adjustment in operating income				$ 3,100
Earn-out paid to former owners			CAD 4.0	3,200
Potential earn-out to be paid each year | CAD									CAD 4.0
Potential maximum earn-out to be paid | CAD					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						(1,000)								$ 3,100		9,600
Contingent earn-out liability				$ 0
Estimated contingent earn-out liabilities
Decreases (increase) in contingent earn-out liabilities														$ 3,100		$ 9,600
Parkland
Business acquisition
Earn-out period for operating income projection											3 years	3 years
Net gains on fair value adjustments in operating income															44,600
Net decrease in contingent earn-out liabilities															44,600
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						19,900		$ 19,100		$ 5,600			24,700
Contingent earn-out liability						0		0					$ 0						$ 0
Profit previously recognized on project								5,300
AEG
Business acquisition
Amount recorded as liabilities in accordance with the purchase agreements												$ 21,500
Earn-out period for operating income projection											2 years	2 years
Annual payment amount												$ 11,300
One-time payment												4,500
Earn-out provision paid for meeting second earn out provision						4,500						4,500
Net gains on fair value adjustments in operating income						4,500									13,200
Potential maximum earn-out to be paid												27,100
Minimum operating income threshold to earn contingent consideration during year one												10,000
Minimum operating income threshold to earn contingent consideration during year two												11,000
Operating income to earn maximum consideration during the first year												17,500
Operating income to earn maximum consideration during the second year												$ 18,500
Estimated potential earn-out (as a percent)											79.00%	79.00%
Gain (loss) on change in contingent consideration							$ 8,900			$ (1,000)
Contingent earn-out liability						0
Minimum operating income in both years for earning one-time payment						$ 9,000						$ 9,000
Earn-outs paid to former owners reported as cash used in financing activities								$ 9,100
AEG and Parkland
Business acquisition
Gain (loss) on change in contingent consideration															58,700
Estimated contingent earn-out liabilities
Decreases (increase) in contingent earn-out liabilities															$ 58,700