Debt and Finance Lease Obligations - Narrative (Details) € in Millions			6 Months Ended
		Oct. 24, 2018 USD ($)	Jun. 30, 2019 USD ($)	Feb. 15, 2019 USD ($)	Feb. 15, 2019 EUR (€)	Dec. 31, 2018 USD ($)
FlyOver Iceland Credit Facility
Line of Credit Facility [Line Items]
Maturity date			Mar. 01, 2022
Remaining borrowing capacity on line of credit			$ 1,000,000.0
Revolving credit facility, balance outstanding	[1]		$ 4,552,000
Maximum borrowing capacity on credit facility				$ 5,600,000	€ 5.0
2018 Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Borrowing capacity on line of credit		$ 450,000,000
Additional borrowing capacity on line of credit		250,000,000
Line of Credit borrowings used to support letter of credit		$ 20,000,000
Maturity date		Oct. 24, 2023
Interest coverage ratio			1084.00%
Leverage ratio			224.00%
Financial covenants leverage ratio step up		400.00%
Minimum amount for material acquisition		$ 50,000,000
Annual share repurchase and dividends limit on leverage ratio basis		$ 20,000,000
Leverage ratio required for dividend or share activity		275.00%
Maximum additional dividends amount permitted to distribute		$ 15,000,000
Commitment fee percentage on line of credit			0.30%
Remaining borrowing capacity on line of credit			$ 135,200,000
Revolving credit facility, balance outstanding	[1]		311,244,000			$ 227,792,000
Letters of credit outstanding			$ 3,600,000
2018 Credit Agreement | Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Interest coverage ratio		300.00%
Leverage ratio		350.00%
Top Tier Foreign Subsidiaries | 2018 Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Percent of lenders security interest on capital stock foreign subsidiary		65.00%

[1] Represents the weighted-average interest rate in effect at the respective periods, including any applicable margin. The interest rates do not include amortization of debt issuance costs or commitment fees.