Commitments and Contingencies - Operating Lease Agreements (Details) - Land in Osceola County, Florida [Member] $ in Millions	12 Months Ended			36 Months Ended
	Dec. 31, 2018 USD ($) a	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($) a
Operating Leased Assets [Line Items]
Operating lease term	75 years			75 years
Expiration date of lease under extension	Jan. 31, 2101
Area of leased property | a	65.3			65.3
Annual base payment for operating lease	$ 4.3
Annual base lease expense for operating lease	$ 9.4	$ 9.4	$ 9.4
Percentage of escalation of base rent (as a percent)	3.00%
Contingent rentals				$ 2.2
Non-cash lease expense	$ 5.0	$ 5.1	$ 5.2