Calder Exit Costs - Additional Information (Details) - USD ($)		3 Months Ended	12 Months Ended
	Nov. 08, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Calder exit costs			$ 800,000	$ 2,500,000	$ 13,900,000
Gain (loss) on sale of land		$ 23,700,000	$ 0	$ 23,700,000	0
Land
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of land	$ 23,700,000
Calder Grandstand
Restructuring Cost and Reserve [Line Items]
Long-lived asset impairment					12,700,000
Net book value of asset					$ 0