Financial Commitments (Reconciliation Of Outstanding Debt Balance To Reported Debt Balance) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Less – unamortized discount and deferred issuance cost	$ (52,293)	$ (56,072)
Total debt, net	780,789	759,519
2014 Revolver [Member]
Debt Instrument [Line Items]
Outstanding Long-Term Debt	185,000	152,500
Less – unamortized discount and deferred issuance cost	(3,698)	(4,510)
Total debt, net	181,302	147,990
Term Loan [Member]
Debt Instrument [Line Items]
Outstanding Long-Term Debt	49,500	57,000
Less – unamortized discount and deferred issuance cost	(1,801)	(2,350)
Total debt, net	47,699	54,650
2010 Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Long-Term Debt	300,000	300,000
Less – unamortized discount and deferred issuance cost	(1,626)	(1,880)
Total debt, net	298,374	298,120
Convertible Notes [Member]
Debt Instrument [Line Items]
Outstanding Long-Term Debt	200,000	200,000
Less – unamortized discount and deferred issuance cost	(45,168)	(47,332)
Total debt, net	$ 154,832	$ 152,668