Pension Plans and Other Postretirement Benefits Financial Assets Accounted for at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Foreign currency forward contracts, liabilities	[1]	$ 250
Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[2]	690,787		$ 607,694
Total Pension Benefits | Domestic Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		168,945	[3]	169,581	[4]
Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		143,976	[5]	85,007	[6]
Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		287,809	[7]	268,911	[8]
Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		83,127	[9]	80,740	[10]
Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		6,930		3,455
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		3,292	[2]	4,439	[1]	$ 5,620
Other Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		3,292	[7]	4,439	[8]
Quoted Prices in Active Markets for Identical Items (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Foreign currency forward contracts, liabilities		0
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[2]	500,996		513,871
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Domestic Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		166,612	[3]	169,581	[4]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		87,311	[5]	85,007	[6]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		240,143	[7]	255,828	[8]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[9]	0	[10]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		6,930		3,455
Quoted Prices in Active Markets for Identical Items (Level 1) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0		0
Quoted Prices in Active Markets for Identical Items (Level 1) | Other Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[7]	0
Quoted Prices in Active Markets for Similar Items (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Foreign currency forward contracts, liabilities	[1]	250
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[2]	106,664		13,083
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Domestic Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		2,333	[3]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		56,665	[5]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		47,666	[7]	13,083	[8]
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[9]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0		0
Quoted Prices in Active Markets for Similar Items (Level 2) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		3,292	[2]	4,439	[1]
Quoted Prices in Active Markets for Similar Items (Level 2) | Other Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		3,292	[7]	4,439	[8]
Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Foreign currency forward contracts, liabilities		0
Unobservable Inputs (Level 3) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		83,127	[2]	80,740	[2]	$ 123,599
Unobservable Inputs (Level 3) | Total Pension Benefits | Domestic Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[3]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[5]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	[7]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		83,127	[9]	80,740	[10]
Unobservable Inputs (Level 3) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0		0
Unobservable Inputs (Level 3) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0		0
Unobservable Inputs (Level 3) | Other Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 0	[7]	$ 0

[1] As a result of our global operating and financing activities, we are exposed to market risks from changes in foreign currency exchange rates, which may adversely affect our operating results and financial position. When deemed appropriate, we minimize our risks from foreign currency exchange rate fluctuations through the use of foreign currency forward contracts. Unless otherwise noted, these derivative financial instruments are not designated as hedging instruments under ASC 815, Derivatives and Hedging. The foreign currency forward contracts are valued using broker quotations or market transactions in either the listed or over-the-counter markets. As such, these derivative instruments are classified within Level 2.

[2] See Note 15 “Pension Plans and Other Postretirement Benefits” for further information about fair value measurements of our pension and postretirement plan assets, including the reconciliations of the plans’ Level 3 assets.

[3] Consists primarily of U.S. stock funds that track or are actively managed and measured against the S&P 500 index.

[4] Consists primarily of U.S. stock funds that track or are actively managed and measured against the S&P 500 index.

[5] Consists primarily of international equity funds which invest in common stocks and other securities whose value is based on an international equity index or an underlying equity security or basket of equity securities.

[6] Consists primarily of international equity funds which invest in common stocks and other securities whose value is based on an international equity index or an underlying equity security or basket of equity securities.

[7] Consists primarily of debt obligations issued by governments, corporations, municipalities and other borrowers. Also includes insurance policies.

[8] Consists primarily of debt obligations issued by governments, corporations, municipalities and other borrowers. Also includes insurance policies.

[9] Consists primarily of funds with holdings in private investment companies. See additional information about the Absolute Return investments below.

[10] Consists primarily of funds with holdings in private investment companies. See additional information about the Absolute Return investments below.