Commitments and Contingencies (Management Agreements) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) property	Mar. 31, 2018 USD ($)	Mar. 31, 2019 hotel	Mar. 31, 2016 hotel
Other Commitments
Number of Hotel Properties Operated under Management Agreements | hotel			150
Number of Real Estate Properties	151		14	41
Minimum
Other Commitments
Management Agreement Term	3 years
Base Management Fee as Percentage of Hotel Revenues	3.00%
Management Agreements which include Franchise Agreement, Base Management Fee as Percentage of Hotel Revenues	3.00%
Maximum
Other Commitments
Management Agreement Term	25 years
Base Management Fee as Percentage of Hotel Revenues	3.50%
Management Agreements which include Franchise Agreement, Base Management Fee as Percentage of Hotel Revenues	7.00%
Management Service [Member]
Other Commitments
Cost of Goods and Services Sold | $	$ 14.1	$ 15.9