Significant Accounting Policies - Revenue Disaggregation and Customer-Related Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,282,571	$ 816,085
Loyalty credit obligation
Disaggregation of Revenue [Line Items]
Customer-related liabilities	$ 44,600		$ 39,900
Customer-related liabilities, term	6 months
Advance payments on goods and services yet to be provided and unpaid wagers
Disaggregation of Revenue [Line Items]
Customer-related liabilities	$ 31,500		34,300
Customer-related liabilities, long-term	500		$ 700
Gaming
Disaggregation of Revenue [Line Items]
Revenues	1,034,511	654,494
Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	125,194	63,643
Hotel
Disaggregation of Revenue [Line Items]
Revenues	71,409	33,521
Racing
Disaggregation of Revenue [Line Items]
Revenues	8,076	6,810
Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		28,184
Other
Disaggregation of Revenue [Line Items]
Revenues	43,381	29,433
Operating segments | Northeast segment
Disaggregation of Revenue [Line Items]
Revenues	550,578	458,719
Operating segments | Northeast segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues	487,727	392,278
Operating segments | Northeast segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	35,797	23,303
Operating segments | Northeast segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues	7,154	4,720
Operating segments | Northeast segment | Racing
Disaggregation of Revenue [Line Items]
Revenues	6,525	5,276
Operating segments | Northeast segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		21,844
Operating segments | Northeast segment | Other
Disaggregation of Revenue [Line Items]
Revenues	13,375	11,298
Operating segments | South segment
Disaggregation of Revenue [Line Items]
Revenues	291,942	63,330
Operating segments | South segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues	220,091	50,976
Operating segments | South segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	40,190	8,430
Operating segments | South segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues	22,980	2,480
Operating segments | South segment | Racing
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating segments | South segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		0
Operating segments | South segment | Other
Disaggregation of Revenue [Line Items]
Revenues	8,681	1,444
Operating segments | West segment
Disaggregation of Revenue [Line Items]
Revenues	158,654	97,966
Operating segments | West segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues	92,823	46,571
Operating segments | West segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	27,870	19,849
Operating segments | West segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues	31,641	21,121
Operating segments | West segment | Racing
Disaggregation of Revenue [Line Items]
Revenues	17	7
Operating segments | West segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		6,340
Operating segments | West segment | Other
Disaggregation of Revenue [Line Items]
Revenues	6,303	4,078
Operating segments | Midwest segment
Disaggregation of Revenue [Line Items]
Revenues	271,262	185,534
Operating segments | Midwest segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues	233,755	164,669
Operating segments | Midwest segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	21,038	11,798
Operating segments | Midwest segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues	9,634	5,200
Operating segments | Midwest segment | Racing
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating segments | Midwest segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		0
Operating segments | Midwest segment | Other
Disaggregation of Revenue [Line Items]
Revenues	6,835	3,867
Other
Disaggregation of Revenue [Line Items]
Revenues	10,135	10,536
Other | Gaming
Disaggregation of Revenue [Line Items]
Revenues	115	0
Other | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues	299	263
Other | Hotel
Disaggregation of Revenue [Line Items]
Revenues	0	0
Other | Racing
Disaggregation of Revenue [Line Items]
Revenues	1,534	1,527
Other | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues		0
Other | Other
Disaggregation of Revenue [Line Items]
Revenues	$ 8,187	$ 8,746