Commitments And Contingencies (Schedule Of Future Minimum Revenues Under Subleases) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018	$ 28,392
2019	24,184
2020	20,712
2021	17,352
2022	14,031
Thereafter	57,869
Total	$ 162,540