Operating Expenses (Schedule Of Depreciation And Amortization Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Expenses [Abstract]
Depreciation expense	$ 35,374	$ 39,966	$ 39,655
Amortization expense	6,658	4,570	3,625
Total depreciation and amortization expenses	$ 42,032	$ 44,536	$ 43,280