v2.4.0.8
Supplemental cash flow information (Cash Flows) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 28, 2013
Sep. 29, 2012
Sep. 28, 2013
Sep. 29, 2012
Jun. 29, 2013
Dec. 29, 2012
Jun. 30, 2012
Dec. 31, 2011
Increase (Decrease) Operating Capital [Line Items]                
Increase (Decrease) in Receivables $ 572 $ (3,319) $ (6,869) $ (21,223)        
Increase (Decrease) in Inventories 1,847 6,623 7,351 11,831        
Increase (Decrease) in Accrued Taxes Payable 942 1,682 1,313 3,179        
Increase (Decrease) in Prepaid Expense and Other Assets 1,649 (57) 3,415 2,837        
Increase (Decrease) in Accounts Payable and Accrued Liabilities (3,605) 3,619 (13,183) (1,191)        
Increase (Decrease) in Deferred Revenue and Customer Advances and Deposits (3,267) (1,086) 1,126 2,646        
Increase Decrease In Operating Capital 1,862 (7,462) 6,847 1,921        
Cash and cash equivalents 6,819 4,187 6,819 4,187 6,460 6,840 3,247 2,378
Opta Minerals Inc [Member]
               
Increase (Decrease) Operating Capital [Line Items]                
Cash and cash equivalents $ 3,226   $ 3,226     $ 3,966