Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		15 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Dec. 20, 2018	Apr. 05, 2017
Derivative [Line Items]
Interest expense related to payments on interest rate swaps	$ 7,146	$ 8,110
Increase (decrease) in fair value of derivative contracts	(9,853)	$ 5,982
Term Loan
Derivative [Line Items]
Outstanding debt	$ 700,000		$ 700,000
Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount					$ 400,000	$ 400,000
Ineffectiveness recognized			$ 0
Interest Rate Swap | Term Loan
Derivative [Line Items]
Outstanding debt					400,000
Interest Rate Swap | Term Loan Maturing April 27, 2022
Derivative [Line Items]
Derivative instruments, notional amount					200,000	200,000
Weighted average effective fixed interest rate	3.90%		3.90%
Interest Rate Swap | Term Loan Maturing December 17,2021
Derivative [Line Items]
Derivative instruments, notional amount					$ 200,000	$ 200,000
Weighted average effective fixed interest rate						3.30%
Average variable interest rate	1.30%		1.30%
Interest Rate Swap | Term Loan Maturing December 17 2023
Derivative [Line Items]
Derivative instruments, notional amount	$ 100,000		$ 100,000
Interest Rate Swap | Term Loan Maturing April 27 2024
Derivative [Line Items]
Derivative instruments, notional amount	100,000		100,000
Interest Rate Swap | Term Loan Maturing January 2, 2020
Derivative [Line Items]
Derivative instruments, notional amount	$ 200,000		$ 200,000
Weighted average effective fixed interest rate	3.90%		3.90%
Average variable interest rate	1.30%		1.30%
Cash flow hedging | Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount	$ 1,000,000		$ 1,000,000	$ 1,000,000
Derivative Asset, fair Value	1,900		1,900	5,300
Derivative Liability, fair Value	7,700		7,700	3,000
Derivative, Fair Value, Net	$ (5,819)		$ (5,819)	$ 2,343