Retirement Plans - Summary of Categories in Fair Value Hierarchy (Details 9) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair values of pension plan assets
Total	$ 290,795	$ 329,581
Equity Securities | U.S.
Fair values of pension plan assets
Total	56,696	174,153
Equity Securities | non-U.S.
Fair values of pension plan assets
Total	11,028	14,050
Equity Funds
Fair values of pension plan assets
Total	17,522	0
Equity Funds | U.S.
Fair values of pension plan assets
Total	0	13,077
Equity Funds | non-U.S.
Fair values of pension plan assets
Total	26,903	0
Equity Funds | International LP
Fair values of pension plan assets
Total	0	15,636
Corporate Bond
Fair values of pension plan assets
Total	0	47,417
Bond funds - government
Fair values of pension plan assets
Total	47,800	0
Bond funds - other
Fair values of pension plan assets
Total	69,617	0
Real estate
Fair values of pension plan assets
Total	10,006	0
Cash and Cash Equivalents
Fair values of pension plan assets
Total	7,417	5,889
Debt securities issued by U.S. and U.K., states and local governments
Fair values of pension plan assets
Total	0	14,484
Partnership
Fair values of pension plan assets
Total	13,360	11,239
Long/short equity-focused hedge funds
Fair values of pension plan assets
Total	5,255	5,367
International hedge funds
Fair values of pension plan assets
Total	25,191	11,679
Mortgage-backed securities
Fair values of pension plan assets
Total	0	3,796
Fixed Annuities
Fair values of pension plan assets
Total	0	12,475
Other asset-backed securities
Fair values of pension plan assets
Total	0	319
Quoted Prices in Active Markets (Level 1)
Fair values of pension plan assets
Total	75,141	194,090
Quoted Prices in Active Markets (Level 1) | Equity Securities | U.S.
Fair values of pension plan assets
Total	56,696	174,153
Quoted Prices in Active Markets (Level 1) | Equity Securities | non-U.S.
Fair values of pension plan assets
Total	11,028	14,048
Quoted Prices in Active Markets (Level 1) | Cash and Cash Equivalents
Fair values of pension plan assets
Total	7,417	5,889
Significant Other Observable Inputs (Level 2)
Fair values of pension plan assets
Total	171,848	94,731
Significant Other Observable Inputs (Level 2) | Equity Securities | non-U.S.
Fair values of pension plan assets
Total	0	2
Significant Other Observable Inputs (Level 2) | Equity Funds
Fair values of pension plan assets
Total	17,522
Significant Other Observable Inputs (Level 2) | Equity Funds | U.S.
Fair values of pension plan assets
Total		13,077
Significant Other Observable Inputs (Level 2) | Equity Funds | non-U.S.
Fair values of pension plan assets
Total	26,903
Significant Other Observable Inputs (Level 2) | Equity Funds | International LP
Fair values of pension plan assets
Total		15,636
Significant Other Observable Inputs (Level 2) | Corporate Bond
Fair values of pension plan assets
Total		47,417
Significant Other Observable Inputs (Level 2) | Bond funds - government
Fair values of pension plan assets
Total	47,800
Significant Other Observable Inputs (Level 2) | Bond funds - other
Fair values of pension plan assets
Total	69,617
Significant Other Observable Inputs (Level 2) | Real estate
Fair values of pension plan assets
Total	10,006
Significant Other Observable Inputs (Level 2) | Debt securities issued by U.S. and U.K., states and local governments
Fair values of pension plan assets
Total		14,484
Significant Other Observable Inputs (Level 2) | Mortgage-backed securities
Fair values of pension plan assets
Total		3,796
Significant Other Observable Inputs (Level 2) | Other asset-backed securities
Fair values of pension plan assets
Total		319
Significant Unobservable Inputs (Level 3)
Fair values of pension plan assets
Total	43,806	40,760
Significant Unobservable Inputs (Level 3) | Partnership
Fair values of pension plan assets
Total	13,360	11,239	$ 9,010
Significant Unobservable Inputs (Level 3) | Long/short equity-focused hedge funds
Fair values of pension plan assets
Total	5,255	5,367	11,147
Significant Unobservable Inputs (Level 3) | International hedge funds
Fair values of pension plan assets
Total	25,191	11,679	10,958
Significant Unobservable Inputs (Level 3) | Fixed Annuities
Fair values of pension plan assets
Total	$ 0	$ 12,475	$ 1,620