Employee Benefit Plans Components of Net Periodic Pension Cost (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Multi-employer benefit expense	$ 1,197	$ 1,158	$ 1,168
Multi-employer pension withdrawal penalty	0	0	39
U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	59	64	59
Interest cost	555	519	513
Expected return on assets	739	623	576
Amortization of actuarial loss	0	(292)	(252)
Total Company defined benefit net periodic pension cost (income)	125	(252)	(248)
Multi-employer benefit expense	1,197	1,158	1,303
Multi-employer pension withdrawal penalty	0	0	39
Net periodic pension cost	1,072	1,410	1,590
UK
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	2,204	2,046	2,371
Expected return on assets	1,861	1,661	1,680
Amortization of actuarial loss	(76)	(36)	(92)
Total Company defined benefit net periodic pension cost (income)	(419)	(421)	(783)
Multi-employer benefit expense	0	0	0
Multi-employer pension withdrawal penalty	0	0	0
Net periodic pension cost	$ 419	$ 421	$ 783