Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013
U.S. Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 14	$ 16	$ 28	$ 32
Interest cost	140	130	280	260
Expected return on assets	(186)	(156)	(372)	(312)
Recognized actuarial net loss	2	71	4	144
Total defined benefit net periodic pension cost	(30)	61	(60)	124
Multiemployer benefit expense	311	295	569	547
Net periodic pension cost	281	356	509	671
UK Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	562	524	1,114	1,055
Expected return on assets	(474)	(408)	(940)	(822)
Recognized actuarial net loss	19	10	37	21
Total defined benefit net periodic pension cost	107	126	211	254
Multiemployer benefit expense	0	0	0	0
Net periodic pension cost	$ 107	$ 126	$ 211	$ 254