Condensed Consolidating Financial Information (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Long-term Debt, Gross	$ 2,858,000	$ 2,706,000
Parent Percentage of Ownership in Guarantor Subsidiaries	100.00%
4.75% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.75%
5.00% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Senior Notes [Member] | 4.75% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term Debt, Gross	$ 600,000	600,000
Senior Notes [Member] | 5.00% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term Debt, Gross	$ 1,000,000	$ 0