Income taxes (Tax reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2016	Jan. 03, 2015	Dec. 28, 2013
Income Tax Disclosure [Abstract]
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ (1,728)	$ 8,356	$ (42)
Income Tax Reconciliation, Foreign Income Tax Rate Differential	(3,097)	3,570	2,996
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance	4,015	1,082	2,990
Income Tax Reconciliation, Nondeductible Expense, Impairment Losses	0	1,122	2,799
Income Tax Reconciliation Impairment Loss On Investment	(4,029)	0	0
Income Tax Reconciliation, Benefits of losses and credits not previously recognized	0	(621)	0
Income Tax Reconciliation, U.S. domestic manufacturing deduction	0	(906)	0
Income Tax Reconciliation Benefit Of Cross Jurisdictional Financing Structures	0	0	(204)
Income Tax Reconciliation Nondeductible Acquisition Costs	910	0	0
Unrecognized Tax Benefits, Period Increase (Decrease)	(855)	(335)	153
Income Tax Reconciliation Nondeductible Expense Other	1,190	0	0
Income Tax Reconciliation, Change in Enacted Tax Rate	(208)	(161)	29
Income Tax Reconciliation, Other Reconciling Items	412	(64)	(298)
Income Tax Expense (Benefit), Continuing Operations, Total	$ (3,390)	$ 12,043	$ 8,423