Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 5,753	$ 4,298	$ 17,316	$ 12,978
Defined contribution plan expense	7,601	8,295	24,612	25,537
U.S. Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	3,915	3,722	11,746	11,164
Interest cost	5,790	6,314	17,372	18,943
Expected return on plan assets	(10,392)	(10,398)	(31,178)	(31,195)
Prior service cost (income)	225	271	673	812
Recognized actuarial (gain) loss	3,155	2,073	9,465	6,217
Transition obligation	0	0	0	0
Other	0	0	810	0
Net periodic benefit cost	2,693	1,982	8,888	5,941
Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,655	1,282	5,006	4,327
Interest cost	1,482	1,710	4,444	5,716
Expected return on plan assets	(2,012)	(1,771)	(6,042)	(5,882)
Prior service cost (income)	22	22	67	76
Recognized actuarial (gain) loss	665	183	2,001	626
Transition obligation	(15)	1	3	3
Other	2	2	5	5
Net periodic benefit cost	1,799	1,429	5,484	4,871
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	934	830	2,804	2,490
Interest cost	1,266	1,537	3,797	4,611
Prior service cost (income)	1,731	1,944	5,195	5,831
Recognized actuarial (gain) loss	71	(107)	214	(320)
Net periodic benefit cost	4,002	4,204	12,010	12,612
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	41	63	122	187
Interest cost	128	156	384	470
Prior service cost (income)	(93)	(103)	(279)	(307)
Recognized actuarial (gain) loss	(8)	14	(23)	40
Net periodic benefit cost	$ 68	$ 130	$ 204	$ 390