Employee Benefit Plans - Schedule of Fair Value of Plan Assets (Details) - Pension - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 356,347	$ 272,974	$ 289,390
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	334,751	244,383
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21,596	28,591
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,462	3,459
Money market mutual funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,462	3,459
Money market mutual funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market mutual funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - value stock fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,827	22,533
Mutual funds - value stock fund | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,827	22,533
Mutual funds - value stock fund | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - value stock fund | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	158,030	115,500
Mutual funds - fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	158,030	115,500
Mutual funds - fixed income | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - fixed income | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - international stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,332	29,441
Mutual funds - international stock | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,332	29,441
Mutual funds - international stock | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - international stock | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - institutional stock index
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,100	73,450
Mutual funds - institutional stock index | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,100	73,450
Mutual funds - institutional stock index | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - institutional stock index | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21,596	28,591
Commingled real estate funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled real estate funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21,596	28,591
Commingled real estate funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0