|**Pension Plans And Other Postretirement Benefits (Tables)**   | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
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|**Pension Plans And Other Postretirement Benefits [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Components Of Net Periodic Benefit Costs                       | ﻿﻿﻿
				
				Pension Benefits﻿
				
				Three Months Ended﻿
				
				March 31,﻿
				
				2019
				
				2018﻿Service cost
				
				$
				680
				
				$
				812﻿Interest cost
				
				
				2,954
				
				
				2,874﻿Expected return on plan assets
				
				
				(3,818)
				
				
				(4,553)﻿Amortization of prior service cost
				
				
				155
				
				
				132﻿Amortization of actuarial loss
				
				
				1,982
				
				
				1,823﻿Net periodic benefit cost
				
				$
				1,953
				
				$
				1,088﻿﻿
				
				Other﻿
				
				Postretirement Benefits﻿
				
				
				Three Months Ended﻿
				
				
				March 31,﻿
				
				2019
				
				2018﻿Service cost
				
				$
				205
				
				$
				262﻿Interest cost
				
				
				750
				
				
				708﻿Expected return on plan assets
				
				
				(621)
				
				
				(677)﻿Amortization of prior service cost
				
				
				(116)
				
				
				(127)﻿Amortization of actuarial loss
				
				
				166
				
				
				296﻿Net periodic benefit cost
				
				$
				384
				
				$
				462
		﻿
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|﻿Service cost                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Interest cost                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Expected return on plan assets                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Amortization of prior service cost                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Amortization of actuarial loss                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Net periodic benefit cost                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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|﻿Service cost                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Interest cost                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Expected return on plan assets                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Amortization of prior service cost                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Amortization of actuarial loss                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|﻿Net periodic benefit cost                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

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