Employee Benefit Plans (Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	$ (101,241)
Net actuarial loss(2)	(46,008)	[1]	$ (2,452)	$ (8,359)
Plan amendment	0	[1]	0	3,610
Amortization of prior service credit(2)	(181)	[1]	(3,516)	(3,713)
Amortization of actuarial loss(2)	6,371	[1]	5,525	7,191
Settlement cost	2,460	[1]	202	0
Total other comprehensive loss	(36,337)		(4,891)	(14,810)
Accumulated Other Comprehensive Income, Ending Balance	(137,578)		(101,241)
Pension Plan [Member]
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	(58,584)		(62,279)	(63,257)
Net actuarial loss(2)	(46,543)		(971)	(8,938)
Plan amendment	0		0	3,610
Amortization of prior service credit(2)	(181)		(181)	0
Amortization of actuarial loss(2)	5,622		4,645	6,306
Settlement cost	2,460		202	0
Total other comprehensive loss	(38,642)		3,695	978
Accumulated Other Comprehensive Income, Ending Balance	(97,226)		(58,584)	(62,279)
Other Postretirement Benefits [Member]
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	(7,881)		(3,945)	(1,696)
Net actuarial loss(2)	535		(1,481)	579
Plan amendment	0		0	0
Amortization of prior service credit(2)	0		(3,335)	(3,713)
Amortization of actuarial loss(2)	749		880	885
Settlement cost	0		0	0
Total other comprehensive loss	1,284		(3,936)	(2,249)
Accumulated Other Comprehensive Income, Ending Balance	$ (6,597)		$ (7,881)	$ (3,945)

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