Commitments and Contingencies - Litigation (Details) - Opry Mills, Nashville, TN - USD ($) $ in Millions		1 Months Ended	2 Months Ended	3 Months Ended
	Jan. 26, 2018	May 31, 2010	Aug. 31, 2015	Mar. 31, 2015
Insurance
Insurance proceeds funded by insurers		$ 50.0
Minimum insurance coverage		50.0
Additional insurance proceeds		$ 150.0
Summary judgment on amount of available coverage limit	$ 50.0
Positive Outcome of Litigation
Insurance
Damages awarded, including amounts previously paid			$ 204.1
Positive Outcome of Litigation | Maximum
Insurance
Summary judgment of additional insurance coverage available under excess insurance policy				$ 150.0