Retirement Benefit Plans (Obligation and Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in benefit obligation
Actuarial (gain) loss	$ (1,300)	$ (5,000)
Amounts recognized in the balance sheets consist of:
Noncurrent liabilities	(10,046)	(10,616)
U.S. Pension Plan
Change in benefit obligation
Benefit obligation at beginning of year	72,839	65,099
Interest cost	2,627	2,754	$ 2,766
Actuarial (gain) loss	(2,884)	8,736
Benefits paid	(4,393)	(4,262)
Plan amendments	0	0
Foreign currency exchange rate changes	0	0
Settlements	0	0
Intercompany transfers	301	512
Benefit obligation at end of year	68,490	72,839	65,099
Accumulated benefit obligation at end of year	68,490	72,839
Change in plan assets
Fair value of plan assets at beginning of year	68,675	67,170
Actual return on plan assets	110	5,972
Employer contributions	424	496
Benefits paid	(4,393)	(4,262)
Foreign currency exchange rate changes	0	0
Settlements	0	0
Intercompany transfers	77	(701)
Fair value of plan assets at end of year	64,893	68,675	67,170
Funded status at end of year	(3,597)	(4,164)
Amounts recognized in the balance sheets consist of:
Noncurrent assets	4,261	4,304
Current liabilities	(1,016)	(1,110)
Noncurrent liabilities	(6,842)	(7,358)
Amount recognized in the balance sheets	(3,597)	(4,164)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Abstract]
Actuarial loss	28,041	26,925
Prior service credit	1,054	955
Deferred taxes	(11,324)	(10,683)
Currency differences and other	0	0
Accumulated other comprehensive income (loss)	17,771	17,197
Non-U.S. Pension Plan
Change in benefit obligation
Benefit obligation at beginning of year	4,549	4,603
Interest cost	152	196	197
Actuarial (gain) loss	(146)	301
Benefits paid	(146)	(151)
Plan amendments	0	0
Foreign currency exchange rate changes	(712)	(400)
Settlements	(178)	0
Intercompany transfers	0	0
Benefit obligation at end of year	3,519	4,549	4,603
Accumulated benefit obligation at end of year	3,519	4,549
Change in plan assets
Fair value of plan assets at beginning of year	5,286	5,186
Actual return on plan assets	256	690
Employer contributions	17	20
Benefits paid	(146)	(151)
Foreign currency exchange rate changes	(852)	(459)
Settlements	(178)	0
Intercompany transfers	0	0
Fair value of plan assets at end of year	4,383	5,286	5,186
Funded status at end of year	864	737
Amounts recognized in the balance sheets consist of:
Noncurrent assets	864	737
Current liabilities	0	0
Noncurrent liabilities	0	0
Amount recognized in the balance sheets	864	737
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Abstract]
Actuarial loss	737	1,110
Prior service credit	0	0
Deferred taxes	(250)	(426)
Currency differences and other	(102)	(43)
Accumulated other comprehensive income (loss)	385	641
Other Postretirement Benefit Plans, Defined Benefit
Change in benefit obligation
Benefit obligation at beginning of year	3,534	3,109
Service cost	70	70	77
Interest cost	113	118	98
Actuarial (gain) loss	226	613
Benefits paid	(477)	(376)
Benefit obligation at end of year	3,466	3,534	$ 3,109
Change in plan assets
Benefits paid	(477)	(376)
Funded status at end of year	(3,466)	(3,534)
Amounts recognized in the balance sheets consist of:
Current liabilities	(262)	(276)
Noncurrent liabilities	(3,204)	(3,258)
Amount recognized in the balance sheets	(3,466)	(3,534)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Abstract]
Actuarial loss	1,140	1,005
Prior service credit	(202)	(309)
Deferred taxes	263	475
Accumulated other comprehensive income (loss)	$ 1,201	$ 1,171