Long-Term Lease Transaction - Additional Information (Details)		12 Months Ended
	Mar. 01, 1996 USD ($)	Dec. 31, 2016 USD ($) Installment	Dec. 31, 2015 USD ($)
Sale Leaseback Transaction [Line Items]
Lease term	48 years 9 months 18 days
Lease value	$ 315,000,000
Leaseback term	21 years 9 months 18 days
Deferred gain	$ 23,700,000
Unamortized portion of the deferred gain		$ 1,100,000	$ 2,200,000
Payment undertaking agreement		306,100,000
Debt considered to be extinguished by in substance defeasance		306,100,000	$ 307,300,000
Fixed purchase price		$ 430,500,000
Number of installments | Installment		4
Lease repayment under payment undertaking agreement		$ 289,700,000
Repayment of long-term lease transaction with owner trust		32,200,000
United States Treasury Securities [Member]
Sale Leaseback Transaction [Line Items]
Lease repayment fund		$ 108,600,000