Employee Benefits (Schedule of fair value of pension plan assets, by fair value hierarchy) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 19,609	$ 20,628
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	19,609	20,628
Defined Benefit Pension Plan | Investment in separate accounts fixed income
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	14,315	15,372
Defined Benefit Pension Plan | Investment in separate accounts equity
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	5,294	5,256
Quoted Prices in Active Markets for Identical Assets (Level 1) | Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	19,609	20,628
Quoted Prices in Active Markets for Identical Assets (Level 1) | Defined Benefit Pension Plan | Investment in separate accounts fixed income
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	14,315	15,372
Quoted Prices in Active Markets for Identical Assets (Level 1) | Defined Benefit Pension Plan | Investment in separate accounts equity
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 5,294	$ 5,256