Pension, Other Postretirement Benefits and Employee Savings and Investment Plans (Assets Carried at Fair Value by Level) (Details) - Pension Benefits - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Pension assets	$ 191,652	$ 180,056	$ 171,778
Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension assets	2,691	6,223
Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension assets	187,601	167,544
Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension assets	1,360	6,289
Pooled separate accounts
Defined Benefit Plan Disclosure [Line Items]
Pension assets	1,216	4,610
Pooled separate accounts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Pooled separate accounts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension assets	1,216	4,610
Pooled separate accounts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Fixed income bonds
Defined Benefit Plan Disclosure [Line Items]
Pension assets	186,385	162,934
Fixed income bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Fixed income bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension assets	186,385	162,934
Fixed income bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension assets	2,691	6,223
Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension assets	2,691	6,223
Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Guaranteed deposit account
Defined Benefit Plan Disclosure [Line Items]
Pension assets	1,360	6,289
Guaranteed deposit account | Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Guaranteed deposit account | Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Guaranteed deposit account | Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension assets	$ 1,360	$ 6,289