Employee Benefit Plans (Pension Plan Assets Fair Value Measurements) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 127	$ 1,990
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	93,167	106,192	$ 103,781
Pension Benefits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175	2,322
Pension Benefits | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	59,261	47,337
Pension Benefits | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	127
Pension Benefits | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,161	2,245
Pension Benefits | Insurance contracts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Insurance contracts | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,161	2,245
Pension Benefits | Insurance contracts | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Cash, mutual funds and common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175	173
Pension Benefits | Cash, mutual funds and common stock | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175	173
Pension Benefits | Cash, mutual funds and common stock | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Cash, mutual funds and common stock | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	2,149
Pension Benefits | U.S. equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	2,149
Pension Benefits | U.S. equity securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | U.S. equity securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Common collective trusts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48,126	35,064
Pension Benefits | Common collective trusts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Pension Benefits | Common collective trusts | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48,126	35,064
Pension Benefits | Common collective trusts | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Common collective trusts at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33,731	56,406
Pension Benefits | Common collective trusts at NAV | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Pension Benefits | Common collective trusts at NAV | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Common collective trusts at NAV | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,974
Pension Benefits | Mutual Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Pension Benefits | Mutual Funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,974
Pension Benefits | Mutual Funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0
Pension Benefits | Investment Partnership
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		10,155
Pension Benefits | Investment Partnership | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Pension Benefits | Investment Partnership | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		10,028
Pension Benefits | Investment Partnership | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 127