Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Amortization of:
Contribution to pension plans				$ 10,600
Estimated total contributions	$ 22,000			22,000
One time charge related to pension settlement (pre-tax)	5,454	$ 0		5,454	$ 0
One-time non-cash charge			$ 7,700
Pre-tax increase to AOCI			$ 12,800
Pension Benefits
Amortization of:
Net pension expense	18,294	12,950		44,201	46,968
Company-administered plans | Pension Benefits
Components of net periodic benefit cost
Service cost	3,165	2,660		9,431	9,065
Interest cost	21,609	22,754		64,524	72,086
Expected return on plan assets	(22,822)	(22,601)		(68,012)	(68,353)
Amortization of:
Net actuarial loss	8,336	7,324		24,863	23,889
Prior service cost	133	320		399	3,060
Net pension expense	10,421	10,457		31,205	39,747
Company-administered plans | U.S. | Pension Benefits
Amortization of:
Net pension expense	10,929	10,952		32,787	41,389
Company-administered plans | Non-U.S. | Pension Benefits
Amortization of:
Net pension expense	(508)	(495)		(1,582)	(1,642)
Union-administered plans | Pension Benefits
Amortization of:
Net pension expense	$ 7,873	$ 2,493		$ 12,996	$ 7,221