Fair Value Measurements And Derivative Instruments (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements And Derivative Instruments [Abstract]
Unrealized gain (loss) recognized in accumulated other comprehensive income	$ 1,839	$ (108)	$ 18
Unrealized gain (loss) reclassified from accumulated other comprehensive income to interest expense	610
Gain (loss) to be reclassified to interest expense during next 12 months	161
Carrying value of debt	1,103,327	1,169,964
Estimated fair value of debt	$ 1,098,248	$ 1,170,901
Impairment of Discontinued Assets			$ 1,800