Retirement Plans (Details 10) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	$ 202,981		$ 175,952
Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	155,839		132,830
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	865		1,677
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	46,277		41,445		35,963
U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	135,887		128,516		106,572
U.S. Pension Plans | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	127,843		120,841
U.S. Pension Plans | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	710		650
U.S. Pension Plans | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,334		7,025
U.S. Pension Plans | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	124,405	[1]	117,718	[2]
U.S. Pension Plans | Mutual Funds [Member] | Large-Cap U S Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	43.00%		41.00%
U.S. Pension Plans | Mutual Funds [Member] | International Growth Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	31.00%		33.00%
U.S. Pension Plans | Mutual Funds [Member] | Fixed Income Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	26.00%		26.00%
U.S. Pension Plans | Mutual Funds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	124,405	[1]	117,718	[2]
U.S. Pension Plans | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	3,438	[3]	3,123	[3]
U.S. Pension Plans | Equity Securities | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	3,438	[3]	3,123	[3]
U.S. Pension Plans | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	710	[4]	650	[4]
U.S. Pension Plans | Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	710	[4]	650	[4]
U.S. Pension Plans | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,334	[5]	7,025	[5]
U.S. Pension Plans | Hedge Funds [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,334	[5]	7,025	[5]	6,266
U.S. Retiree Healthcare Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,526		6,616		5,357
U.S. Retiree Healthcare Plan | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,371		5,589
U.S. Retiree Healthcare Plan | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	155		1,027
U.S. Retiree Healthcare Plan | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,371	[6]	5,589	[7]
U.S. Retiree Healthcare Plan | Mutual Funds [Member] | Large-Cap U S Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	52.00%		58.00%
U.S. Retiree Healthcare Plan | Mutual Funds [Member] | International Growth Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	20.00%		12.00%
U.S. Retiree Healthcare Plan | Mutual Funds [Member] | Fixed Income Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	28.00%		30.00%
U.S. Retiree Healthcare Plan | Mutual Funds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	7,371	[6]	5,589	[7]
U.S. Retiree Healthcare Plan | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	155	[4]	1,027	[4]
U.S. Retiree Healthcare Plan | Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	155	[4]	1,027	[4]
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	59,568		40,820		35,859
Non-U.S. Pension Plans | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	20,625		6,400
Non-U.S. Pension Plans | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	38,943		34,420
Non-U.S. Pension Plans | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	9,258	[8]
Non-U.S. Pension Plans | Mutual Funds [Member] | International Growth Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	26.00%
Non-U.S. Pension Plans | Mutual Funds [Member] | Fixed Income Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of plan asset categories	74.00%
Non-U.S. Pension Plans | Mutual Funds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	9,258	[8]
Non-U.S. Pension Plans | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	11,367	[4]	6,400	[4]
Non-U.S. Pension Plans | Cash and Cash Equivalents [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	11,367	[4]	6,400	[4]
Non-U.S. Pension Plans | Bank and Insurance Investment Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	38,943	[9]	34,420	[9]
Non-U.S. Pension Plans | Bank and Insurance Investment Contracts [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit plan assets	$ 38,943	[9]	$ 34,420	[9]	$ 29,697

[1] The mutual fund balance in the U.S. Pension Plans are invested in the following categories: 43% in the common stock of large-cap U.S. companies, 31% in the common stock of international growth companies, and 26% in fixed income bonds issued by U.S. companies and by the U.S. government and its agencies.

[2] The mutual fund balance in the U.S. Pension Plans are invested in the following categories: 41% in the common stock of large-cap U.S. companies, 33% in the common stock of international growth companies, and 26% in fixed income bonds issued by U.S. companies and by the U.S. government and its agencies.

[3] Represents primarily amounts invested in common stock of technology, healthcare, financial, energy and consumer staples and discretionary U.S. companies.

[4] Primarily represents money market funds held with various financial institutions.

[5] Hedge fund invests in both short and long term U.S. common stocks. Management of the hedge funds has the ability to shift investments from value to growth strategies, from large to small capitalization stocks and from a net long position to a net short position.

[6] The mutual fund balance in the U.S. Retiree Healthcare Plan is invested in the following categories: 52% in the common stock of large-cap U.S. companies, 20% in the common stock of international growth companies and 28% in fixed income bonds of U.S. companies and U.S. government.

[7] The mutual fund balance in the U.S. Retiree Healthcare Plan is invested in the following categories: 58% in the common stock of large-cap U.S. companies, 12% in the common stock of international growth companies and 30% in fixed income bonds of U.S. companies and U.S. government.

[8] The mutual fund balance in the Non-U.S. Pension Plans is invested in the following categories: 74% in international bonds and 26% in the common stock of international companies.

[9] Amount represents bank and insurance guaranteed investment contracts.