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PENSION AND OTHER POSTRETIREMENT BENEFITS - PLAN ASSETS BY CATEGORY (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2016
USD ($)
category
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 149,032 $ 144,568 $ 154,729
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 149,032 144,568  
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 154,729 149,032  
Pension Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 28 28 52
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 28    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 52 28  
Pension Benefits | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 692 692 376
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 692    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 376 692  
Pension Benefits | STIF-Type Instrument      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,096 1,096 1,168
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,096    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 1,168 1,096  
Pension Benefits | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 41,976 41,976 42,369
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 41,976    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 42,369 41,976  
Pension Benefits | U.S. Large-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 11,535 11,535 14,523
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 11,535    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 14,523 11,535  
Pension Benefits | U.S. Mid-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 2,748 2,748 2,024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 2,748    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 2,024 2,748  
Pension Benefits | U.S. Small-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 210 210 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 210    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 210  
Pension Benefits | Equity Securities, International Securities      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,367 1,367 2,727
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,367    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 2,727 1,367  
Pension Benefits | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 26,800 26,800 27,017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 26,800    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 27,017 26,800  
Pension Benefits | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 40,853 40,853 44,873
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 40,853    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 44,873 40,853  
Pension Benefits | Common/Collective Trust Fund – Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Total 6,866 6,866 7,506
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 6,866    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 7,506 6,866  
Pension Benefits | Guaranteed Insurance Contract      
Defined Benefit Plan Disclosure [Line Items]      
Total 8,031 8,031 7,930
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 8,031    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 7,930 8,031  
Pension Benefits | Hedge Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 3,353 3,353 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 3,353    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 3,353  
Pension Benefits | Private Equity Fund      
Defined Benefit Plan Disclosure [Line Items]      
Total 3,477 3,477 4,164
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 3,477    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year $ 4,164 3,477  
Pension Benefits | Private Equity Fund | Minimum      
Actual return on plan assets:      
Lag period for fund valuations 90 days    
Pension Benefits | Private Equity Fund | Maximum      
Actual return on plan assets:      
Lag period for fund valuations 120 days    
Pension Benefits | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 15,888 15,888 19,326
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 15,888    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 19,326 15,888  
Pension Benefits | Level 1 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 28 28 52
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 28    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 52 28  
Pension Benefits | Level 1 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | STIF-Type Instrument      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | U.S. Large-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 11,535 11,535 $ 14,523
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 11,535    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 14,523 11,535  
Number of equity investment sectors (in categories) | category     5
Pension Benefits | Level 1 | U.S. Mid-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 2,748 2,748 $ 2,024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 2,748    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 2,024 2,748  
Pension Benefits | Level 1 | U.S. Small-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 210 210 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 210    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 210  
Pension Benefits | Level 1 | Equity Securities, International Securities      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,367 1,367 2,727
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,367    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 2,727 1,367  
Pension Benefits | Level 1 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Common/Collective Trust Fund – Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Guaranteed Insurance Contract      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Hedge Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 1 | Private Equity Fund      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Total 111,417 111,417 115,803
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 111,417    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 115,803 111,417  
Pension Benefits | Level 2 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 692 692 376
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 692    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 376 692  
Pension Benefits | Level 2 | STIF-Type Instrument      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,096 1,096 1,168
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,096    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 1,168 1,096  
Pension Benefits | Level 2 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 41,976 41,976 42,369
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 41,976    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 42,369 41,976  
Pension Benefits | Level 2 | U.S. Large-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | U.S. Mid-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | U.S. Small-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 0   0
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0    
Pension Benefits | Level 2 | Equity Securities, International Securities      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 26,800 26,800 27,017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 26,800    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 27,017 26,800  
Pension Benefits | Level 2 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 40,853 40,853 44,873
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 40,853    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 44,873 40,853  
Pension Benefits | Level 2 | Common/Collective Trust Fund – Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | Guaranteed Insurance Contract      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | Hedge Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 2 | Private Equity Fund      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Total 21,727 21,089 19,600
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 21,727 21,089  
Actual return on plan assets:      
Relating to assets still held at the reporting date 1,097 514  
Relating to assets sold during the period 212 367  
Purchases, Sales and Settlements (3,436) (243)  
Fair Value of Plan Assets at End of Year 19,600 21,727  
Pension Benefits | Level 3 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | STIF-Type Instrument      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | U.S. Large-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | U.S. Mid-Cap      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Equity Securities, International Securities      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Common/Collective Trust Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Pension Benefits | Level 3 | Common/Collective Trust Fund – Real Estate      
Defined Benefit Plan Disclosure [Line Items]      
Total 6,866 5,987 7,506
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 6,866 5,987  
Actual return on plan assets:      
Relating to assets still held at the reporting date 640 879  
Relating to assets sold during the period 0 0  
Purchases, Sales and Settlements 0 0  
Fair Value of Plan Assets at End of Year 7,506 6,866  
Pension Benefits | Level 3 | Guaranteed Insurance Contract      
Defined Benefit Plan Disclosure [Line Items]      
Total 8,031 8,738 7,930
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 8,031 8,738  
Actual return on plan assets:      
Relating to assets still held at the reporting date 541 (26)  
Relating to assets sold during the period 12 21  
Purchases, Sales and Settlements (654) (702)  
Fair Value of Plan Assets at End of Year 7,930 8,031  
Pension Benefits | Level 3 | Hedge Funds      
Defined Benefit Plan Disclosure [Line Items]      
Total 3,353 3,469 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 3,353 3,469  
Actual return on plan assets:      
Relating to assets still held at the reporting date (13) (116)  
Relating to assets sold during the period 0 0  
Purchases, Sales and Settlements (3,340) 0  
Fair Value of Plan Assets at End of Year 0 3,353  
Pension Benefits | Level 3 | Private Equity Fund      
Defined Benefit Plan Disclosure [Line Items]      
Total 3,477 2,895 4,164
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 3,477 2,895  
Actual return on plan assets:      
Relating to assets still held at the reporting date (71) (223)  
Relating to assets sold during the period 200 346  
Purchases, Sales and Settlements 558 459  
Fair Value of Plan Assets at End of Year 4,164 3,477  
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Total 43,428 40,951 45,948
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 43,428 40,951  
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 45,948 43,428  
Other Postretirement Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 26 26 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 26    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year $ 0 26  
Other Postretirement Benefits | Equity Securities, U.S. Securities | Minimum      
Actual return on plan assets:      
Target plan allocations 30.00%    
Other Postretirement Benefits | Equity Securities, U.S. Securities | Maximum      
Actual return on plan assets:      
Target plan allocations 43.00%    
Other Postretirement Benefits | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 12,154 12,154 13,372
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 12,154    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 13,372 12,154  
Other Postretirement Benefits | Mutual Fund - U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,228 1,228  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year $ 1,228    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   1,228  
Other Postretirement Benefits | Equity Securities, International Securities | Minimum      
Actual return on plan assets:      
Target plan allocations 20.00%    
Other Postretirement Benefits | Equity Securities, International Securities | Maximum      
Actual return on plan assets:      
Target plan allocations 30.00%    
Other Postretirement Benefits | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 7,471 7,471 7,796
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 7,471    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 7,796 7,471  
Other Postretirement Benefits | Mutual Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 922 922  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year $ 922    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   922  
Other Postretirement Benefits | Fixed Income Funds | Minimum      
Actual return on plan assets:      
Target plan allocations 32.00%    
Other Postretirement Benefits | Fixed Income Funds | Maximum      
Actual return on plan assets:      
Target plan allocations 42.00%    
Other Postretirement Benefits | Common/Collective Trust Fund – Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 11,852 11,852 12,167
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 11,852    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 12,167 11,852  
Other Postretirement Benefits | Mutual Funds - Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,352 1,352  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year $ 1,352    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   1,352  
Other Postretirement Benefits | Other Investments | Minimum      
Actual return on plan assets:      
Target plan allocations 0.00%    
Other Postretirement Benefits | Other Investments | Maximum      
Actual return on plan assets:      
Target plan allocations 7.00%    
Other Postretirement Benefits | Mutual Funds - REITs      
Defined Benefit Plan Disclosure [Line Items]      
Total $ 142 142  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 142    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   142  
Other Postretirement Benefits | Company Owned Life Insurance      
Defined Benefit Plan Disclosure [Line Items]      
Total 8,281 8,281 12,613
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 8,281    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 12,613 8,281  
Other Postretirement Benefits | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Total 3,670 3,670 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 3,670    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 3,670  
Other Postretirement Benefits | Level 1 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 26 26 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 26    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 26  
Other Postretirement Benefits | Level 1 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 1 | Mutual Fund - U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,228 1,228  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,228    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   1,228  
Other Postretirement Benefits | Level 1 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 1 | Mutual Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 922 922  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 922    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   922  
Other Postretirement Benefits | Level 1 | Common/Collective Trust Fund – Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 1 | Mutual Funds - Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 1,352 1,352  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 1,352    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   1,352  
Other Postretirement Benefits | Level 1 | Mutual Funds - REITs      
Defined Benefit Plan Disclosure [Line Items]      
Total 142 142  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 142    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   142  
Other Postretirement Benefits | Level 1 | Company Owned Life Insurance      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Total 39,758 39,758 45,948
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 39,758    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 45,948 39,758  
Other Postretirement Benefits | Level 2 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 2 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 12,154 12,154 13,372
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 12,154    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 13,372 12,154  
Other Postretirement Benefits | Level 2 | Mutual Fund - U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 2 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 7,471 7,471 7,796
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 7,471    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 7,796 7,471  
Other Postretirement Benefits | Level 2 | Mutual Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 2 | Common/Collective Trust Fund – Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 11,852 11,852 12,167
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 11,852    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 12,167 11,852  
Other Postretirement Benefits | Level 2 | Mutual Funds - Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 2 | Mutual Funds - REITs      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 2 | Company Owned Life Insurance      
Defined Benefit Plan Disclosure [Line Items]      
Total 8,281 8,281 12,613
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 8,281    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 12,613 8,281  
Other Postretirement Benefits | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 3 | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 3 | Common/Collective Trust Funds – U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 3 | Mutual Fund - U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 3 | Common/Collective Trust Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 3 | Mutual Funds - International      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 3 | Common/Collective Trust Fund – Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year 0 0  
Other Postretirement Benefits | Level 3 | Mutual Funds - Bonds      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 3 | Mutual Funds - REITs      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0  
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year   0  
Other Postretirement Benefits | Level 3 | Company Owned Life Insurance      
Defined Benefit Plan Disclosure [Line Items]      
Total 0 0 $ 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair Value of Plan Assets at Beginning of Year 0    
Actual return on plan assets:      
Fair Value of Plan Assets at End of Year $ 0 $ 0