Pensions and Other Post-Employment Benefits (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension and other post-retirement benefits (Textual) [Abstract]
Increase graded assumption for the domestic rate of compensation	4.00%	4.00%
Maturity Of debt securities	five years or less
Mutual fund that typically invests at least of its assets in equity and debt securities	80.00%
Period of written notice for withdrawals from multi-strategy hedge fund partnerships	10 days
Target funded status percentage	100.00%
Current asset allocation to invest in alternative securities, maximum	25.00%
Domestic defined benefit pension plan	$ 21,000,000
Other defined benefit plan estimated future employer contributions in next fiscal year	1,400,000
Liability for other post-employment arrangements	93,225,000	$ 91,505,000
Company's annual contributions	4,500,000	3,600,000	$ 3,100,000
Foreign Plan [Member]
Pension and other post-retirement benefits (Textual) [Abstract]
Liability for other post-employment arrangements	2,100,000	$ 2,400,000
Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Lump sum program payments	$ 100,000
Equity securities | Minimum [Member]
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	30.00%
Equity securities | Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	60.00%
Fixed Income Funds | Minimum [Member]
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	20.00%
Fixed Income Funds | Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50.00%
Change in Accounting Method Accounted for as Change in Estimate [Member]
Pension and other post-retirement benefits (Textual) [Abstract]
DefinedBenefitPensionPlanChangeInEstimateOnServiceandInterestCost	$ 1,000,000.00