Commitments (Schedule Of Future Minimum Lease Payments Under Noncancelable Operating Leases And Future Minimum Capital Lease Payments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Commitments [Abstract]
Capital Leases, 2018	$ 1,712
Capital Leases, 2019	1,746
Capital Leases, 2020	1,781
Capital Leases, 2021	1,816
Capital Leases, 2022	1,853
Capital Leases, thereafter	465
Capital Leases, total minimum lease payments	9,373
Less: amount representing interest	2,201
Present value of minimum lease payments	7,172
Less: current installments	1,025	$ 896
Capital lease obligations, less current installments	6,147	$ 7,172
Operating Leases, 2018	13,750
Operating Leases, 2019	12,342
Operating Leases, 2020	10,086
Operating Leases, 2021	7,980
Operating Leases, 2022	5,743
Operating Leases, thereafter	19,226
Operating Leases, total minimum lease payments	$ 69,127