Debt (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2016 USD ($) Debt / EBITDA Interest / Debt	Dec. 31, 2015 USD ($)
Schedule of long term debt [Abstract]
Long term debt		$ 583,033	$ 613,877
Less debt fees		(253)	(375)
Total long-term debt		582,780	613,502
Aggregate amounts of contractual maturities of long-term debt for the next five years [Abstract]
Amounts due in 2017		103,800
Amounts due in 2018		38,900
Amounts due in 2019		17,100
Amounts due in 2020		236,900
Amounts due in 2021		100
Stand-by letters of credit outstanding		6,800	6,300
Short-term borrowings [Abstract]
Short-term borrowings		$ 20,578	$ 20,655
Weighted-average interest rates on short-term borrowings		2.26%	1.62%
Maximum [Member]
Debt covenants [Abstract]
Debt to EBITDA, actual | Debt / EBITDA	[1]	2.51
Debt to adjusted EBITDA, required | Debt / EBITDA	[1]	3.50
Minimum [Member]
Debt covenants [Abstract]
Interest coverage, actual | Interest / Debt		7.35
Interest coverage, required | Interest / Debt		2.00
Long-term Revolving Credit Facility [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 162,079	$ 103,343
Credit facility, amount		520,000
Long term debt additional disclosures [Abstract]
Remaining borrowing capacity		41,000
Revolving Credit Facility [Member]
Schedule of long term debt [Abstract]
Credit facility, amount		$ 350,000
Long term debt additional disclosures [Abstract]
Average effective interest rate		1.40%	1.36%
Remaining borrowing capacity		$ 256,000
Uncommitted Loans [Member]
Short-term borrowings [Abstract]
Short-term borrowings		20,435	$ 18,580
Loans of Foreign Subsidiaries [Member]
Short-term borrowings [Abstract]
Short-term borrowings		143	2,075
3.66% Senior Notes due November 2023 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 75,000	75,000
Interest rate, stated percentage		3.66%
Term loan, maturity date		Nov. 30, 2023
3.06% Euro-denominated Senior Notes due November 2023 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 40,226	41,545
Interest rate, stated percentage		3.06%
Term loan, maturity date		Nov. 30, 2023
1.85% Euro-denominated Senior Notes due November 2022 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 70,316	72,623
Interest rate, stated percentage		1.85%
Term loan, maturity date		Nov. 30, 2022
4.47% Senior Notes due November 2018 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 25,000	25,000
Interest rate, stated percentage		4.47%
Term loan, maturity date		Nov. 30, 2018
4.14% Senior Notes due November 2017 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 25,000	25,000
Interest rate, stated percentage		4.14%
Term loan, maturity date		Nov. 30, 2017
4.91% Senior Notes due through May 2017 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 66,000	77,000
Interest rate, stated percentage		4.91%
Term loan, maturity date		May 31, 2017
3.77% Senior Notes due November 2016 [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 0	25,000
Interest rate, stated percentage		3.77%
Term loan, maturity date		Nov. 30, 2016
Term Loan [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 118,313	167,875
Term loan, face amount		$ 170,000
Term Loan [Member] | Revolving Credit Facility [Member]
Schedule of long term debt [Abstract]
Credit facility maturity date		Nov. 06, 2020
Term Loan [Member] | Revolving Credit Facility [Member] | LIBOR [Member]
Schedule of long term debt [Abstract]
Interest rate		1.50%
Various Other Notes [Member]
Schedule of long term debt [Abstract]
Long term debt		$ 1,099	$ 1,491

[1] Debt to EBITDA is defined in the Company's debt covenants as total funded debt divided by the Company's consolidated operating income excluding non-operating gains and losses and depreciation and amortization.