Employee Benefit Plans (Plan Assets at Fair Value) (Details) - Employee Pension Plans [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	$ 71,541	$ 66,057	$ 72,296
Quoted prices in active markets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	40,793	26,949
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	2,390	2,437
Cash and Cash Equivalents [Member] | Quoted prices in active markets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	2,390	2,437
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	18,031	14,023
Fixed Income Funds [Member] | Quoted prices in active markets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	18,031	14,023
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	20,372	10,489
Equity Funds [Member] | Quoted prices in active markets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	20,372	10,489
Non-Closely Held Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	40,793	26,949
Non-Closely Held Funds [Member] | Quoted prices in active markets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	40,793	26,949
Equity Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	8,711	6,931
Hedge Funds Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	22,037	32,177
Closely Held Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan's assets	$ 30,748	$ 39,108