Employee Benefits (Schedule of Fair Value of Qualified Pension Plan Assets) (Details) - Qualified Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 93,749	$ 86,180	$ 87,364
Asset allocations by category	100.00%	100.00%
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 52,103	$ 51,435
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41,646	34,745
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 9,902	$ 25,986
Asset allocations by category	10.60%	30.20%
Cash and cash equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 9,902	$ 25,986
Cash and cash equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of U.S government-sponsored enterprises [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28,615	21,787
Obligations of U.S government-sponsored enterprises [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of U.S government-sponsored enterprises [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28,615	21,787
Obligations of U.S government-sponsored enterprises [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of states and political subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,998	2,597
Obligations of states and political subdivisions [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of states and political subdivisions [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,998	2,597
Obligations of states and political subdivisions [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,033	10,361
Corporate bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Corporate bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,033	10,361
Corporate bonds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,593	9,957
Common stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,593	9,957
Common stocks [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Common stocks [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,608	15,492
Mutual funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,608	15,492
Mutual funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0
Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations by category	44.40%	40.30%
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations by category	45.00%	29.50%