Fair Value Measurement (Carrying Values And Fair Values Of The Company's Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 2,819,263	$ 2,667,808
Long-term Debt, Fair Value	2,863,355	2,708,475
Term-A Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	1,245,175	1,386,869
Long-term Debt, Fair Value	1,254,855	1,370,850
5.00% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	981,949
Long-term Debt, Fair Value	1,002,500
7.75% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		689,910
Long-term Debt, Fair Value		737,625
4.75% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	592,139	591,029
Long-term Debt, Fair Value	$ 606,000	$ 600,000