Summary of Significant Accounting Policies -Revenue Recognition, Player Loyalty Programs, and Gaming and Racing Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue Recognition and Promotional Allowances
Promotional allowances	$ 48,843	$ 45,643	$ 136,684	$ 130,327
Cost of complimentary services	16,024	14,816	45,181	42,729
Gaming and Racing Taxes
Gaming expense	252,900	245,000	751,800	739,500
Rooms
Revenue Recognition and Promotional Allowances
Promotional allowances	11,076	10,257	30,570	29,477
Cost of complimentary services	1,528	1,419	4,264	3,954
Food And Beverage
Revenue Recognition and Promotional Allowances
Promotional allowances	35,293	32,977	99,245	94,295
Cost of complimentary services	13,691	12,488	38,312	36,212
Other
Revenue Recognition and Promotional Allowances
Promotional allowances	2,474	2,409	6,869	6,555
Cost of complimentary services	$ 805	$ 909	$ 2,605	$ 2,563