Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net periodic benefit cost [Abstract]
Total amount amortized out of accumulated other comprehensive income	$ 5,775	$ 4,341	$ 11,563	$ 8,680
Defined contribution plan expense	8,005	8,865	17,011	17,242
U.S. Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	3,916	3,721	7,831	7,442
Interest cost	5,791	6,315	11,582	12,629
Expected return on plan assets	(10,393)	(10,399)	(20,786)	(20,797)
Prior service cost (income)	224	270	448	541
Recognized actuarial (gain) loss	3,155	2,072	6,310	4,144
Transition obligation	0	0	0	0
Settlement loss	0	0	0	0
Other	0	0	810	0
Net periodic benefit cost	2,693	1,979	6,195	3,959
Foreign Pension Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	1,663	1,530	3,351	3,045
Interest cost	1,476	2,023	2,962	4,006
Expected return on plan assets	(2,011)	(2,082)	(4,030)	(4,111)
Prior service cost (income)	22	27	45	54
Recognized actuarial (gain) loss	661	222	1,336	443
Transition obligation	9	2	18	2
Settlement loss	0	0	0	3
Other	1	0	3	0
Net periodic benefit cost	1,821	1,722	3,685	3,442
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit cost [Abstract]
Service cost	935	830	1,870	1,660
Interest cost	1,265	1,537	2,531	3,074
Prior service cost (income)	1,732	1,943	3,464	3,887
Recognized actuarial (gain) loss	72	(106)	143	(213)
Net periodic benefit cost	4,004	4,204	8,008	8,408
Post-Retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	40	62	81	124
Interest cost	128	157	256	314
Prior service cost (income)	(93)	(102)	(186)	(204)
Recognized actuarial (gain) loss	(7)	13	(15)	26
Net periodic benefit cost	$ 68	$ 130	$ 136	$ 260