Debt And Financing-Credit Agreement (Details) - USD ($) $ in Thousands			9 Months Ended
		Jul. 27, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Proceeds from long-term debt			$ 0	$ 684,504
Proceeds from revolving line of credit			(150,000)	$ 143,000
Repayments of Debt		$ 4,900
2014 Agreement, Old Revolver [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		450,000
Extinguishment of Debt, Amount		0
2014 Agreement, Old Term Loan A [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		500,000
Extinguishment of Debt, Amount		485,000
2014 Agreement, Term Loan B [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		400,000
Extinguishment of Debt, Amount		395,000
2015 Agreement, New Term Loan A [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			680,000
Proceeds from long-term debt		680,000
2015 Agreement, New Revolver [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	[1]		$ 600,000
Proceeds from revolving line of credit		$ 200,000

[1] The commitment fee for the unused portion of the New Revolver is based on the Company's consolidated leverage ratio and ranges from 0.25% to 0.35%. As of September 30, 2016, commitment fees on the unused portion of the New Revolver accrued at 0.25% and outstanding letter of credit fees accrued at 1.50%. As of December 31, 2015, commitment fees on the unused portion of the New Revolver accrued at 0.25% and outstanding letter of credit fees accrued at 1.75%