Employee Benefit Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	$ 69,308	$ 59,737	$ 65,728
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	69,308	59,737
Pension | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	35,317	30,281
Pension | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	33,991	29,456
Pension | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | U.S. equities, Large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	17,698	15,141
Pension | U.S. equities, Large cap | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | U.S. equities, Large cap | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	17,698	15,141
Pension | U.S. equities, Large cap | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | U.S. equities, Medium cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,404	2,912
Pension | U.S. equities, Medium cap | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | U.S. equities, Medium cap | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,404	2,912
Pension | U.S. equities, Medium cap | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | U.S. equities, Small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	2,720	2,330
Pension | U.S. equities, Small cap | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	1,360	1,165
Pension | U.S. equities, Small cap | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	1,360	1,165
Pension | U.S. equities, Small cap | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Non-U.S. equities, Large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	12,919	11,065
Pension | Non-U.S. equities, Large cap | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	12,919	11,065
Pension | Non-U.S. equities, Large cap | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Non-U.S. equities, Large cap | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Non-U.S. equities, Emerging markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	4,060	3,494
Pension | Non-U.S. equities, Emerging markets | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	4,060	3,494
Pension | Non-U.S. equities, Emerging markets | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Non-U.S. equities, Emerging markets | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Money markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,381	2,912
Pension | Fixed-income securities, Money markets | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Money markets | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,381	2,912
Pension | Fixed-income securities, Money markets | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, U.S. bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	13,569	11,647
Pension | Fixed-income securities, U.S. bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	10,172	8,735
Pension | Fixed-income securities, U.S. bonds | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,397	2,912
Pension | Fixed-income securities, U.S. bonds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Non-U.S. bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	6,806	5,822
Pension | Fixed-income securities, Non-U.S. bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	6,806	5,822
Pension | Fixed-income securities, Non-U.S. bonds | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Non-U.S. bonds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,395	2,912
Pension | Fixed-income securities, Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Real estate | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	3,395	2,912
Pension | Fixed-income securities, Real estate | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Common/collective trusts
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	1,356	1,502
Pension | Fixed-income securities, Common/collective trusts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	0	0
Pension | Fixed-income securities, Common/collective trusts | Significant Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	1,356	1,502
Pension | Fixed-income securities, Common/collective trusts | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total assets	$ 0	$ 0