Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-term debt and other long-term liabilites [Abstract]
Credit agreement with average interest rates of 2.8% and 2.6% at December 31, 2016 and 2015, respectively	$ 160,800	$ 281,000
6.625% senior subordinated notes due 2021	650,000	650,000
Total principal amount	810,800	931,000
Less: unamortized discount	(2,804)	(3,338)
Less: debt issuance costs, net	(7,079)	(8,667)
Total long-term debt	$ 800,917	$ 918,995
Line of Credit Facility, Interest Rate at Period End	2.80%	2.60%