Summary Of Significant Accounting Policies (Schedule Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 12,436	$ 4,202
Change excluding amounts reclassified from accumulated other comprehensive loss	(571)	10,633
Amounts reclassified from accumulated other comprehensive loss	(4,221)	(2,399)
Net other comprehensive loss (income)	(4,792)	8,234	$ (20,541)
Ending balance	7,644	12,436	4,202
Gain On Investments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(656)	(340)
Change excluding amounts reclassified from accumulated other comprehensive loss	$ 99	(354)
Amounts reclassified from accumulated other comprehensive loss		38
Net other comprehensive loss (income)	$ 99	(316)
Ending balance	(557)	(656)	(340)
Gain On Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,416)	(1,233)
Change excluding amounts reclassified from accumulated other comprehensive loss	(1,946)	(131)
Amounts reclassified from accumulated other comprehensive loss	(2,798)	(2,052)
Net other comprehensive loss (income)	(4,744)	(2,183)
Ending balance	(8,160)	(3,416)	(1,233)
Defined Benefit Pension Plan [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	16,508	5,775
Change excluding amounts reclassified from accumulated other comprehensive loss	1,276	11,118
Amounts reclassified from accumulated other comprehensive loss	(1,423)	(385)
Net other comprehensive loss (income)	(147)	10,733
Ending balance	$ 16,361	$ 16,508	$ 5,775