Fixed Assets (Schedule Of Fixed Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Fixed assets, at cost	$ 298,355	$ 291,776	$ 279,699
Less accumulated depreciation and amortization	147,977	141,176	130,612
Fixed assets, net	$ 150,378	$ 150,600	$ 149,087