Retirement Benefits - Recurring Fair Value Measures (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 |
Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | $ 6,341 | $ 5,918 | $ 6,289 |
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 4 | 5,916 | |
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 6,337 | 0 | |
Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 2 | |
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 898,550 | 834,655 | |
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 6,341 | 5,918 | |
Mutual Funds | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 5,916 | |
Mutual Funds | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 6,337 | 0 | |
Mutual Funds | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Mutual Funds | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 6,337 | 5,916 | |
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 65,266 | 73,006 | |
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 2,470 | 9,148 | |
US Treasury and Government [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
US Treasury and Government [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 67,736 | 82,154 | |
Cash and cash equivalents | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 3,638 | 4,612 | |
Cash and cash equivalents | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | (540) | 3,223 | |
Cash and cash equivalents | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Cash and cash equivalents | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 3,098 | 7,835 | |
Equity Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 343,888 | 325,081 | |
Equity Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 20,088 | 22,205 | |
Equity Investments [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 534,574 | 487,369 | |
Net Receivables [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Net Receivables [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Net Receivables [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Net Receivables [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Net Receivables [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | (23,015) | (44,981) | |
Net Receivables [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 2 | |
Net Receivables [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | (23,015) | (44,981) | |
Net Receivables [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 2 | |
Partnership/Jointed Ventures | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Partnership/Jointed Ventures | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Partnership/Jointed Ventures | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 115,570 | 107,137 | |
Partnership/Jointed Ventures | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 115,570 | 107,137 | |
Collective Investment Funds | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Collective Investment Funds | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Collective Investment Funds | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 359,861 | 342,014 | |
Collective Investment Funds | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 359,861 | 342,014 | |
Other Security Investments | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Other Security Investments | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Other Security Investments | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 1,434 | 1,096 | |
Other Security Investments | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 1,434 | 1,096 | |
Mutual Fund | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Mutual Fund | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Mutual Fund | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 80,724 | 82,103 | |
Mutual Fund | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 80,724 | 82,103 | |
Corporate Bond Securities - Foreign | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Corporate Bond Securities - Foreign | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 5,239 | 3,699 | |
Corporate Bond Securities - Foreign | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Corporate Bond Securities - Foreign | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 5,239 | 3,699 | |
Corporate Bond Securities - US | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Corporate Bond Securities - US | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 12,820 | 6,082 | |
Corporate Bond Securities - US | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Corporate Bond Securities - US | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 12,820 | 6,082 | |
Common Stock - US | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 249,021 | 228,247 | |
Common Stock - US | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 99 | 53 | |
Common Stock - US | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Common Stock - US | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 249,120 | 228,300 | |
Common Stock - Foreign | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 25,963 | 19,216 | |
Common Stock - Foreign | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Common Stock - Foreign | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Common Stock - Foreign | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 25,963 | 19,216 | |
Money Market Funds | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 4 | 0 | |
Money Market Funds | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Money Market Funds | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Money Market Funds | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value, Measurements, Recurring | Other Pension Plan [Member] | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of plan assets | $ 4 | $ 0 | |