Long Term Obligations - Fan Pier Leases (Details) $ in Thousands, ft² in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2011 ft² lease building
Lessee, Lease, Description [Line Items]
Depreciation expense	$ 61,400	$ 60,800	$ 60,000
Rental expense	19,200	19,100	18,100
Property and equipment, net	789,437	698,362
Fan Pier Leases
Lessee, Lease, Description [Line Items]
Number of leases | lease				2
Area of real estate property (in square feet) | ft²				1.1
Lease agreements number of buildings | building				2
Optional term of lease agreement (in years)				10 years
Buildings | Fan Pier Leases
Lessee, Lease, Description [Line Items]
Interest expense	60,100	60,200	60,200
Depreciation expense	13,300	13,300	13,300
Rental expense	6,500	6,500	$ 6,500
Construction financing lease obligation, current and noncurrent	472,100	472,600
Construction in Progress | Fan Pier Leases
Lessee, Lease, Description [Line Items]
Property and equipment, net	$ 475,700	$ 489,000