Employee Retirement Benefit Plans: Components of Net Periodic Benefit Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2013	Jun. 29, 2012	Jun. 28, 2013	Jun. 29, 2012
Pension Plans, Defined Benefit
Interest cost	$ 398	$ 467	$ 796	$ 933
Expected return on assets	(460)	(454)	(920)	(907)
Amortization of actuarial loss	177	170	354	341
Settlement charge		317		634
Net periodic benefit expense	115	500	230	1,001
Supplemental Executive Retirement Plan
Interest cost	41	52	82	104
Amortization of actuarial loss	17	14	34	28
Amortization of prior year service cost	(12)	(12)	(24)	(24)
Net periodic benefit expense	$ 46	$ 54	$ 92	$ 108