Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013	Mar. 29, 2015
Defined Benefit Plan Disclosure [Line Items]
Percentage of contributions by plan participants	6.00%
Percentage of employer cash contribution	50.00%
Employee service period, minimum	1 year
Employee service Period, maximum	5 years
Employer contribution under the plans	$ 1,200	$ 1,100	$ 1,100
Percentage of fair value market Price	85.00%
Employee benefit plan expense	$ 6,139	6,158	6,290
Actuarial losses on other postretirement benefits, net of tax	$ (1,014)	$ 0	$ 0
Pension plan participation rate	5.00%
Expected contributions under pension plan	$ 4,300
Discount rate in benefit obligations	2.51%	2.01%
Expected rate of return on plan assets	2.25%	3.90%	4.50%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Percentage of contribution by employee stock purchase plan	1.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Percentage of contribution by employee stock purchase plan	25.00%
Executive Officers
Defined Benefit Plan Disclosure [Line Items]
Percentage of salary contribution by employer	50.00%
Percentage of bonus contribution by employer	100.00%
Employer matching contribution to deferred compensation plan	25.00%
Minimum age of executives for matching contributions to vest immediately	55 years
Matching contribution to deferred stock account	$ 100	$ 100	$ 100
Vesting period, years	3 years
Maximum age for executives to receive three year vesting period	55 years
Director
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution to deferred compensation plan	25.00%
Matching contribution to deferred stock account	$ 38	69	56
Employee Stock Purchase Plan
Defined Benefit Plan Disclosure [Line Items]
Additional shares reserved for future issuance				600,000
Share reserved for future issuance				1,650,000
Employee benefit plan expense	$ 500	$ 600	$ 400
Shares authorized under the plan	520,227
Shares issued under the plan	187,760	123,210	169,143