Segments - Summarized Consolidated Financial Information by Segment (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Reservation fee percentage	2.00%
Owned Hotels [Member]
Segment Reporting Information [Line Items]
Franchise fee percentage	4.50%
Management fee percentage	2.50%
Revenue from owned hotels	$ 68.2	$ 71.5	$ 75.1
Fee charged to owned hotels	$ 133.3	$ 140.1	$ 145.8