Retirement Plans - Accumulated Other Comprehensive loss (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S.Pension Plans
Accumulated Other Comprehensive Loss
Beginning balance	$ 96,194	$ 79,218
Amortization of retirement benefits, net of tax	(2,871)	(3,523)
Settlements and curtailments	0	(106)
Net actuarial gain	4,150	20,605
Foreign exchange impact	0	0
Ending balance	97,473	96,194
U.S.Pension Plans | Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss)
Accumulated Other Comprehensive Loss
Beginning balance	96,194	79,218
Amortization of retirement benefits, net of tax	(2,871)	(3,523)
Settlements and curtailments	0	(106)
Net actuarial gain	4,150	20,605
Foreign exchange impact	0	0
Ending balance	97,473	96,194
U.S.Pension Plans | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit)
Accumulated Other Comprehensive Loss
Beginning balance	0	0
Amortization of retirement benefits, net of tax	0	0
Settlements and curtailments	0	0
Net actuarial gain	0	0
Foreign exchange impact	0	0
Ending balance	0	0
Non-U.S. Pension Plans | Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss)
Accumulated Other Comprehensive Loss
Beginning balance	8,490	4,642
Amortization of retirement benefits, net of tax	(1,507)	(183)
Settlements and curtailments	(5,355)	0
Net actuarial gain	640	4,290
Foreign exchange impact	(629)	(259)
Ending balance	1,639	8,490
Other Post-Retirement Benefit Plan | Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss)
Accumulated Other Comprehensive Loss
Beginning balance	(517)	(755)
Amortization of retirement benefits, net of tax	63	98
Net actuarial gain	(215)	140
Ending balance	$ (669)	$ (517)