Commitments and Contingencies (Insurance) (Details)	3 Months Ended
	Mar. 31, 2017 USD ($)
General Liability
Insurance
Insurance Maximum Coverage Per occurrence	$ 300,000,000
Insurance Maximum Coverage Per Property	300,000,000
All Risk Property And Rental Value
Insurance
Insurance Maximum Coverage Per occurrence	1,700,000,000
Terrorism Coverage Including NBCR
Insurance
Insurance Maximum Coverage Per occurrence	1,700,000,000
Insurance Maximum Coverage In Aggregate	$ 1,700,000,000
NBCR
Insurance
Insurance Coverage End Date	December 2020
Self Insured Responsibility (in percentage)	17.00%
Federal Government Responsibility (in percentage)	83.00%
FNSIC | NBCR
Insurance
Insurance Deductible	$ 293,000