Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013
U.S. Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 14	$ 16	$ 42	$ 48
Interest cost	141	130	421	390
Expected return on assets	(185)	(156)	(557)	(468)
Recognized actuarial net loss	3	73	7	217
Total defined benefit net periodic pension cost	(27)	63	(87)	187
Multiemployer benefit expense	324	313	893	860
Net periodic pension cost	297	376	806	1,047
UK Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	559	527	1,673	1,582
Expected return on assets	(472)	(411)	(1,412)	(1,233)
Recognized actuarial net loss	18	8	55	29
Total defined benefit net periodic pension cost	105	124	316	378
Multiemployer benefit expense	0	0	0	0
Net periodic pension cost	$ 105	$ 124	$ 316	$ 378