Long-Term Debt (Details) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) Rate	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Secured Debt	$ 1,124,000	$ 588,000
Unamortized Debt Issuance Expense	(23,576)	(12,787)
Long-term Debt	1,100,424	575,213
Line of Credit Facility, Maximum Borrowing Capacity	$ 300,000
Pro Forma Consolidated Leverage Ratio \| Rate	3.25%
FeesPaidInConnectionWithAmendment	$ 22,450
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	15,300
Interest Expense, Debt	6,160
Contractual Quarterly Payments	$ 2,100
Leverage ratio	2.69
$200 Million Revolving Credit Facility, Due March 2023 [Member]
Debt Instrument [Line Items]
Secured Debt	$ 0	0
$825 Million Term B Loan Facility, due June 2022 [Member]
Debt Instrument [Line Items]
Secured Debt	337,000	588,000
$822 Million Term B Loan Facility, due April 2025 [Member]
Debt Instrument [Line Items]
Secured Debt	787,000	$ 0
Face amount of term loan	$ 822,000
Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio \| Rate	4.75%
Leverage Ratio in Latest Year of Debt Term \| Rate	3.75%
Term Loan Facility \| Minimum [Member] \| $200 Million Revolving Credit Facility, Due March 2023 [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings \| Rate	0.25%
Revolving credit facility, unused portion, commitment fee percentage \| Rate	0.20%
Term Loan Facility \| Minimum [Member] \| Eurodollar [Member] \| $200 Million Revolving Credit Facility, Due March 2023 [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings \| Rate	1.25%
Term Loan Facility \| Maximum [Member] \| $200 Million Revolving Credit Facility, Due March 2023 [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings \| Rate	1.25%
Revolving credit facility, unused portion, commitment fee percentage \| Rate	0.35%
Term Loan Facility \| Maximum [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate During Period \| Rate	4.52%
Term Loan Facility \| Maximum [Member] \| Eurodollar [Member] \| $200 Million Revolving Credit Facility, Due March 2023 [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings \| Rate	2.25%
Term Loan Facility \| Maximum [Member] \| Eurodollar [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings \| Rate	2.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 195,600

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Fees Paid In Connection With Amendment

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The leverage ratio as defined in the credit agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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