Accounts payable and accrued liabilities (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts Payable, Current	$ 94,992	$ 89,034
Employee-related Liabilities, Current	15,161	14,262
Accrued Grain Liabilities Current	15,039	15,254
Loss Contingency Accrual	6,980	39,750
Interest Payable Current	5,496	5,500
Accrued Product Recall Settlement	2,250	0
Dividends Payable	1,700	1,590
Other Accrued Liabilities, Current	19,746	8,355
Accounts Payable and Accrued Liabilities, Current, Total	$ 161,364	$ 173,745