Equity Investees (Schedule Of Operations For Equity Investees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Revenues	$ 28,501	$ 31,010	$ 57,406	$ 59,439
Operating income	20,038	23,527	40,825	45,059
Net income	$ 18,580	$ 22,385	$ 38,015	$ 42,749