Long-Term Debt - Narrative (Details)		6 Months Ended
	Feb. 16, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Total debt, net of unamortized loan fees		$ 799,896,000	$ 821,958,000
Long-term debt		812,250,000	836,500,000
Unamortized loan fees		$ 12,354,000	14,542,000
Effective rate		3.90%
Principal balance of term loans outstanding, percentage		50.00%
Fixed rate to pay		1.16%
Leverage ratio two		3.25
Leverage ratio three		3.00
Debt service coverage ratio, actual		3.40
Debt instrument covenants minimum liquidity amount		$ 25,000,000
Interest rate reduction, basis points	0.05%
Credit facility modification, charitable contributions	$ 1,500,000.0
Maximum
Debt Instrument [Line Items]
Leverage ratio one		3.75
Minimum
Debt Instrument [Line Items]
Debt service coverage ratio, actual		2.00
Term loan A-1
Debt Instrument [Line Items]
Long-term debt		$ 412,250,000	436,500,000
Periodic payment of principal		6,100,000
Periodic payment principal, period two		12,100,000
Periodic payment principal, period three		$ 18,200,000
Term loan A-1 | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate		2.25%
Term loan A-2
Debt Instrument [Line Items]
Long-term debt		$ 400,000,000	$ 400,000,000
Periodic payment of principal		$ 10,000,000
Term loan A-2 | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate		2.50%