Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Credit agreement with an average interest rate of 2.2% and 2.9% at June 30, 2015 and December 31, 2014, respectively	$ 280,500	$ 166,000
6.625% senior subordinated notes due 2021, net of unamortized discount of $3.6 million and $3.8 million at June 30, 2015 and December 31, 2014, respectively	646,408	646,163
Total long-term debt	$ 926,908	$ 812,163
Revolving credit facility interest rate	2.20%	2.90%
Interest percentage of senior subordinated notes	6.625%
Debt instrument maturity date	May 15, 2021
Debt instrument, unamortized discount	$ 3,600	$ 3,800