Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Credit agreement with an average interest rate of 2.2% and 2.6% at March 31, 2016 and December 31, 2015, respectively	$ 260,200,000	$ 281,000,000
6.625% senior subordinated notes due 2021, net of unamortized discount and debt issuance costs of $11,478 and $12,005 at March 31, 2016 and December 31, 2015, respectively	638,522,000	637,995,000
Total long-term debt	$ 898,722,000	$ 918,995,000
Revolving credit facility interest rate	2.20%	2.60%
Interest percentage of senior subordinated notes	6.625%
Debt instrument maturity date	May 15, 2021
Debt instrument, unamortized discount	$ 3,208,000	$ 3,338,000
Debt instrument, unamortized debt issuance cost	$ 8,270,000	$ 8,667,000