Acquisition (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
	Oct. 01, 2015	Oct. 02, 2012	Sep. 30, 2012	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 21, 2015	Apr. 30, 2015
Settlement reducing cash consideration
Estimated total structural and other improvement and repair costs related to lease contracts						$ 2,300
Central
Acquisitions
Interest acquired (as a percent)		100.00%
Common stock issued (in shares)		6,161,332
Assumption of debt, net of cash acquired		$ 217,675
Maximum Net Debt Working Capital threshold amount		$ 275,000
Period after which contingent cash consideration to be paid		3 years
Price of share at which former stockholders of acquiree can elect to pay applicable amount (in dollars per share)		$ 23.64
Minimum cash consideration to cover capped indemnities		$ 17,000
Settlement reducing cash consideration
Net Debt Working Capital at September 30, 2012 asserted by representative of former stockholders								$ 277,989	$ 270,757
Net Debt Capital difference as of September 30, 2012 below the lower threshold									$ 4,242
Net Debt Capital difference as of September 30, 2012 above the lower threshold								2,989
Net Debt Working Capital due								$ 0
Indemnification of cost pursuant to merger agreement						80.00%
Estimated total structural and other improvement and repair costs related to lease contracts						$ 2,300
Period in which reduction in cash consideration payable for the seller's indemnification made						3 years
Reduction of cash consideration payable				$ 11,334		$ 11,334
Cash consideration payable in three years from the acquisition date, pursuant to the Merger Agreement and prior to Central Net Debt Working Capital and indemnification of certain defined adverse consequences, net		27,000		27,000		27,000
Net Debt Working Capital at September 30, 2012 as defined in the Merger Agreement			$ 296,334	296,334		296,334
Threshold of Net Debt Working Capital, pursuant to the Merger Agreement		$ 285,000		285,000		285,000
Excess over the threshold of Net Debt Working Capital			$ 11,334			(11,334)
Indemnification of certain defined adverse consequences, net						(21,708)
Indemnification claims for Net Debt Working Capital and certain adverse consequences in excess of the $27,000 cash consideration payable in three years from the acquisition date				(6,042)		(6,042)
Indemnification claims for Net Debt Working Capital and certain adverse consequences not recognized due to the contingent nature of these claims				6,042		6,042
Acquisition and integration related costs included in general and administrative expenses				$ 1,613	$ 2,989	$ 3,484	$ 5,031
Central | Subsequent Events
Settlement reducing cash consideration
Net Debt Working Capital at September 30, 2012 asserted by representative of former stockholders	$ 11,334
Estimated total structural and other improvement and repair costs related to lease contracts	1,800
Indemnity claims for certain defined adverse consequences	$ 23,508