Pension and Non-pension Postretirement Benefits (Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Pension Plans and SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,784	$ 1,386	$ 3,693	$ 2,989
Interest cost	4,756	5,241	9,568	10,535
Expected return on plan assets	(6,306)	(6,209)	(12,566)	(12,449)
Amortization of unrecognized:
Prior service cost	44	322	84	644
Loss / (gain)	2,168	1,046	4,460	2,546
Pension expense or non-pension postretirement benefit expense	2,446	1,786	5,239	4,265
Defined Benefit Plan, Contributions [Abstract]
Employer contributions made to defined benefit plans	1,300		2,700
Estimated employer contributions to defined benefit plans in remainder of 2015	2,000
U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,022	807	2,183	1,832
Interest cost	3,649	3,819	7,358	7,689
Expected return on plan assets	(5,668)	(5,585)	(11,330)	(11,193)
Amortization of unrecognized:
Prior service cost	105	264	209	529
Loss / (gain)	1,759	787	3,645	2,029
Pension expense or non-pension postretirement benefit expense	867	92	2,065	886
Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	762	579	1,510	1,157
Interest cost	1,107	1,422	2,210	2,846
Expected return on plan assets	(638)	(624)	(1,236)	(1,256)
Amortization of unrecognized:
Prior service cost	(61)	58	(125)	115
Loss / (gain)	409	259	815	517
Pension expense or non-pension postretirement benefit expense	1,579	1,694	3,174	3,379
Non-Pension Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	146	252	428	504
Interest cost	619	739	1,298	1,476
Amortization of unrecognized:
Prior service cost	35	35	70	70
Loss / (gain)	76	67	272	134
Pension expense or non-pension postretirement benefit expense	876	1,093	2,068	2,184
Defined Benefit Plan, Contributions [Abstract]
Employer contributions made to defined benefit plans	700		1,600
Estimated employer contributions to defined benefit plans in year 2015	5,100
U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	145	251	427	503
Interest cost	609	710	1,269	1,420
Amortization of unrecognized:
Prior service cost	35	35	70	70
Loss / (gain)	100	67	296	134
Pension expense or non-pension postretirement benefit expense	889	1,063	2,062	2,127
Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	1
Interest cost	10	29	29	56
Amortization of unrecognized:
Prior service cost	0	0	0	0
Loss / (gain)	(24)	0	(24)	0
Pension expense or non-pension postretirement benefit expense	$ (13)	$ 30	$ 6	$ 57