Long-Term Debt Long-term Debt Text (Details) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 15, 2015 Rate	Jun. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 05, 2015 USD ($)
Debt Instrument [Line Items]
Long-term Debt		$ 691,930	$ 691,930	$ 755,508
Unamortized Debt Issuance Expense		$ 17,070	$ 17,070	$ 18,500
Debt, Weighted Average Interest Rate		3.70%	3.70%
Contractual Quarterly Payments		$ 2,100	$ 2,100
Leverage Ratio		2.55
$825 Million Term B Loan Facility, due June 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 825,000
$150 Million Revolving Credit Facility, Due June 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 150,000
Maximum [Member]
Debt Instrument [Line Items]
Leverage Ratio in Latest Year of Debt Term		3.25	3.25
Leverage Ratio			4.25
Notes Payable to Banks [Member] | Minimum [Member] | $150 Million Revolving Credit Facility, Due June 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate | Rate	0.75%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.25%
Notes Payable to Banks [Member] | Maximum [Member] | $150 Million Revolving Credit Facility, Due June 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate | Rate	2.50%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.40%
Notes Payable to Banks [Member] | Maximum [Member] | Eurodollar [Member] | $825 Million Term B Loan Facility, due June 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate | Rate	3.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		$ 121,500	$ 121,500