Pension and Non-pension Postretirement Benefits (Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,832	$ 1,483	$ 5,525	$ 4,472
Interest cost	4,763	5,241	14,331	15,776
Expected return on plan assets	(6,274)	(6,213)	(18,840)	(18,662)
Amortization of unrecognized:
Prior service cost	42	320	126	964
Loss / (gain)	2,223	1,267	6,683	3,813
Pension expense or non-pension postretirement benefit expense	2,586	2,098	7,825	6,363
Defined Benefit Plan, Contributions [Abstract]
Employer contributions made to defined benefit plans	1,300		3,800
Estimated employer contributions to defined benefit plans in remainder of 2015	1,400
U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,091	916	3,274	2,748
Interest cost	3,678	3,845	11,036	11,534
Expected return on plan assets	(5,666)	(5,597)	(16,996)	(16,790)
Amortization of unrecognized:
Prior service cost	104	265	313	794
Loss / (gain)	1,823	1,014	5,468	3,043
Pension expense or non-pension postretirement benefit expense	1,030	443	3,095	1,329
Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	741	567	2,251	1,724
Interest cost	1,085	1,396	3,295	4,242
Expected return on plan assets	(608)	(616)	(1,844)	(1,872)
Amortization of unrecognized:
Prior service cost	(62)	55	(187)	170
Loss / (gain)	400	253	1,215	770
Pension expense or non-pension postretirement benefit expense	1,556	1,655	4,730	5,034
Non-Pension Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	214	252	642	756
Interest cost	644	736	1,942	2,212
Amortization of unrecognized:
Prior service cost	35	35	105	105
Loss / (gain)	129	66	401	200
Pension expense or non-pension postretirement benefit expense	1,022	1,089	3,090	3,273
Defined Benefit Plan, Contributions [Abstract]
Employer contributions made to defined benefit plans	800		2,400
Estimated employer contributions to defined benefit plans in year 2015	5,100
U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	214	252	641	755
Interest cost	634	710	1,903	2,130
Amortization of unrecognized:
Prior service cost	35	35	105	105
Loss / (gain)	148	66	444	200
Pension expense or non-pension postretirement benefit expense	1,031	1,063	3,093	3,190
Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	1
Interest cost	10	26	39	82
Amortization of unrecognized:
Prior service cost	0	0	0	0
Loss / (gain)	(19)	0	(43)	0
Pension expense or non-pension postretirement benefit expense	$ (9)	$ 26	$ (3)	$ 83