Retirement Benefit Plans Part 2 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation and Retirement Disclosure [Abstract]
Number of participants in U.S. Pension Plan	447
Number of active employees participating in U.S. Pension Plan	102
Defined Benefit Plans and Other Postretirement Benefit Plans
Discretionary contribution made to pension plan	$ 15,000
Effect of one-percentage-point change in assumed healthcare cost trends
Effect of one-percentage-point decrease on total of service and interest cost components	(54)
Effect of one-percentage-point increase on total of service and interest cost components	61
Effect of one-percentage-point decrease on postretirement benefit obligation	(1,076)
Effect of one-percentage-point increase on postretirement benefit obligation	1,227
U.S. Pension Benenfits
Weighted-average assumptions used to determine benefit obligation
Discount rate	3.79%	4.39%
Rate of compensation increase	3.00%	3.00%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	4.39%	5.39%	5.88%
Expected long-term rate of return on plan assets	7.70%	7.70%	7.70%
Rate of compensation increase	3.00%	3.00%	3.00%
Accumulated benefit obligations
Accumulated benefit obligations	46,907	42,909
Plans with accumulated benefit obligation in excess of plan assets
Projected benefit obligation	48,824	44,280
Accumulated benefit obligation	46,907	42,909
Fair value of plan assets	46,942	28,237
Change in benefit obligation:
Benefit obligation at beginning of year	44,280	38,885
Service cost	686	651	657
Interest cost	1,928	2,013	2,032
Plan participants' contributions	0	0
Plan amendments	0	233
Actuarial loss (gain)	3,893	4,216
Foreign exchange	0	0
Benefits paid	(1,963)	(1,718)
Benefit obligation at end of year	48,824	44,280	38,885
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	28,237	29,483
Actual return on plan assets	3,818	357
Employer contributions	16,850	115
Plan participants' contributions	0	0
Foreign exchange	0	0
Benefits paid	(1,963)	(1,718)
Fair value of plan assets at end of year	46,942	28,237	29,483
Funded status at end of year	(1,882)	(16,043)
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent Assets	698	0
Current liabilities	145	129
Noncurrent liabilities	2,435	15,914
Net accrued liability	1,882	16,043
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Prior service cost	224	606
Net actuarial loss	13,711	12,488
Accumulated other comprehensive income	13,935	13,094
Components of the net periodic benefit cost
Service cost	686	651	657
Interest cost	1,928	2,013	2,032
Expected return on plan assets	(2,279)	(2,325)	(2,340)
Amortization of net actuarial loss	1,131	27	22
Amortization of prior service cost	382	550	554
Foreign currency	0	0	0
Net periodic benefit cost	1,848	916	925
Changes in accumulated other comprehensive income:
Prior service cost	0	233	0
Net acuarial loss (gain)	2,355	6,184	573
Amortization of prior service cost	(382)	(550)	(554)
Amortization of prior transition asset	0	0	0
Amortization of net actuarial (loss) gain	(1,132)	(27)	(22)
Total recognized in other comprehensive income	841	5,840	(3)
Total recognized in net periodic benefit cost and other comprehensive income	2,689	6,756	922
Expected future benefit payments
2013	1,813
2014	2,057
2015	2,373
2016	2,544
2017	2,683
2018 to 2022	14,864
Total	26,334
U.S. Pension Benenfits | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Target allocation of investments	60.00%
U.S. Pension Benenfits | Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Target allocation of investments	40.00%
U.S. Nonqualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contricutions in the next fiscal year	145
Postretirement Medical Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contricutions in the next fiscal year	904
Weighted-average assumptions used to determine benefit obligation
Discount rate	3.27%	4.20%
Rate of compensation increase	0.00%	0.00%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	4.20%	5.00%	5.60%
Expected long-term rate of return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	0.00%	0.00%	0.00%
Assumed healthcare cost trend rates
Healthcare cost trend rate assumption for the next year	9.17%	10.14%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2031	2031
Change in benefit obligation:
Benefit obligation at beginning of year	13,708	13,423
Service cost	142	132	121
Interest cost	551	612	681
Plan participants' contributions	0	0
Plan amendments	0	0
Actuarial loss (gain)	926	72
Foreign exchange	0	0
Benefits paid	(1,237)	(531)
Benefit obligation at end of year	14,090	13,708	13,423
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	1,237	531
Plan participants' contributions	0	0
Foreign exchange	0	0
Benefits paid	(1,237)	(531)
Fair value of plan assets at end of year	0	0	0
Funded status at end of year	(14,090)	(13,708)
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent Assets	0	0
Current liabilities	904	841
Noncurrent liabilities	13,186	12,867
Net accrued liability	14,090	13,708
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Prior service cost	(109)	(689)
Net actuarial loss	2,789	1,921
Accumulated other comprehensive income	2,680	1,232
Components of the net periodic benefit cost
Service cost	142	132	121
Interest cost	551	612	681
Expected return on plan assets	0	0	0
Amortization of net actuarial loss	57	0	0
Amortization of prior service cost	(580)	(580)	(579)
Foreign currency	0	0	0
Net periodic benefit cost	170	164	223
Changes in accumulated other comprehensive income:
Prior service cost	0	0	0
Net acuarial loss (gain)	926	72	(892)
Amortization of prior service cost	580	580	580
Amortization of prior transition asset	0	0	0
Amortization of net actuarial (loss) gain	(57)	0	0
Total recognized in other comprehensive income	1,449	652	(312)
Total recognized in net periodic benefit cost and other comprehensive income	1,619	816	(89)
Expected future benefit payments
2013	904
2014	977
2015	1,070
2016	1,150
2017	1,188
2018 to 2022	5,575
Total	10,864
Amounts that will be amortized from accumulated other comprehensive income (loss) in next fiscal year
Net loss	200
Net prior service cost (credit)	(103)
U.K. Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contricutions in the next fiscal year	234
Accumulated benefit obligations
Accumulated benefit obligations	8,837	7,858
German Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contricutions in the next fiscal year	39
Accumulated benefit obligations
Accumulated benefit obligations	878	652
Non-U.S. Pension Benefits
Weighted-average assumptions used to determine benefit obligation
Discount rate	4.41%	4.94%
Rate of compensation increase	4.50%	4.60%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	4.94%	5.39%	5.69%
Expected long-term rate of return on plan assets	4.80%	5.20%	5.50%
Rate of compensation increase	4.60%	5.10%	5.10%
Plans with accumulated benefit obligation in excess of plan assets
Projected benefit obligation	10,011	8,775
Accumulated benefit obligation	9,715	8,510
Fair value of plan assets	8,855	7,738
Change in benefit obligation:
Benefit obligation at beginning of year	8,775	8,394
Service cost	138	133	117
Interest cost	437	465	434
Plan participants' contributions	24	24
Plan amendments	0	0
Actuarial loss (gain)	595	40
Foreign exchange	411	(63)
Benefits paid	(369)	(218)
Benefit obligation at end of year	10,011	8,775	8,394
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	7,738	6,917
Actual return on plan assets	738	715
Employer contributions	346	352
Plan participants' contributions	24	24
Foreign exchange	378	(52)
Benefits paid	(369)	(218)
Fair value of plan assets at end of year	8,855	7,738	6,917
Funded status at end of year	(1,156)	(1,037)
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent Assets	0	0
Current liabilities	39	38
Noncurrent liabilities	1,117	999
Net accrued liability	1,156	1,037
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Prior service cost	0	0
Net actuarial loss	246	2
Accumulated other comprehensive income	246	2
Components of the net periodic benefit cost
Service cost	138	133	117
Interest cost	437	465	434
Expected return on plan assets	(387)	(376)	(346)
Amortization of net actuarial loss	0	0	0
Amortization of prior service cost	0	0	0
Foreign currency	16	(18)	(65)
Net periodic benefit cost	204	204	140
Changes in accumulated other comprehensive income:
Prior service cost	0	0	0
Net acuarial loss (gain)	244	(300)	143
Amortization of prior service cost	0	0	0
Amortization of prior transition asset	0	0	0
Amortization of net actuarial (loss) gain	0	0	0
Total recognized in other comprehensive income	244	(300)	143
Total recognized in net periodic benefit cost and other comprehensive income	448	(96)	283
Expected future benefit payments
2013	211
2014	252
2015	257
2016	263
2017	304
2018 to 2022	1,966
Total	3,253
Pension Benefits
Amounts that will be amortized from accumulated other comprehensive income (loss) in next fiscal year
Net loss	1,754
Net prior service cost (credit)	$ 73