Summary of Significant Accounting Policies - Revenue Disaggregation and Customer Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Disaggregation of Revenue [Line Items]
Revenues									$ 3,587,918	$ 3,331,466	$ 3,209,041
Less: Promotional allowance									0	(183,496)	(174,661)
Revenues	$ 1,155,269	$ 789,651	$ 826,913	$ 816,085	$ 769,036	$ 806,247	$ 796,463	$ 776,224	3,587,918	3,147,970	3,034,380
Loyalty credit obligation
Disaggregation of Revenue [Line Items]
Customer-related liabilities	39,900								$ 39,900			$ 24,700
Contract with customer, term									6 months
Advance payments on goods and services yet to be provided or unpaid wagers
Disaggregation of Revenue [Line Items]
Customer-related liabilities	34,300				21,500				$ 34,300	21,500
Customer-related liabilities, long-term	$ 700				$ 1,300				700	1,300
Gaming
Disaggregation of Revenue [Line Items]
Revenues									2,894,861	2,692,021	2,606,262
Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									314,812	292,397	286,212
Hotel
Disaggregation of Revenue [Line Items]
Revenues									163,675	129,959	125,404
Racing
Disaggregation of Revenue [Line Items]
Revenues									26,781	62,695	65,990
Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									57,281	26,060	15,997
Other
Disaggregation of Revenue [Line Items]
Revenues									130,508	128,334	109,176
Operating segments | Northeast segment
Disaggregation of Revenue [Line Items]
Revenues									1,891,514	1,818,629	1,804,063
Less: Promotional allowance										(62,050)	(62,254)
Revenues									1,891,514	1,756,579	1,741,809
Operating segments | Northeast segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues									1,644,176	1,583,882	1,572,378
Operating segments | Northeast segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									109,645	114,993	115,834
Operating segments | Northeast segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues									23,208	21,513	20,888
Operating segments | Northeast segment | Racing
Disaggregation of Revenue [Line Items]
Revenues									20,275	49,596	48,063
Operating segments | Northeast segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									46,822	0	0
Operating segments | Northeast segment | Other
Disaggregation of Revenue [Line Items]
Revenues									47,388	48,645	46,900
Operating segments | South segment
Disaggregation of Revenue [Line Items]
Revenues									394,351	255,102	211,690
Less: Promotional allowance										(30,855)	(25,858)
Revenues									394,351	224,247	185,832
Operating segments | South segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues									302,842	202,967	166,509
Operating segments | South segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									56,631	35,532	30,692
Operating segments | South segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues									23,320	10,340	8,843
Operating segments | South segment | Racing
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Operating segments | South segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Operating segments | South segment | Other
Disaggregation of Revenue [Line Items]
Revenues									11,558	6,263	5,646
Operating segments | West segment
Disaggregation of Revenue [Line Items]
Revenues									437,887	423,301	399,559
Less: Promotional allowance										(42,883)	(38,783)
Revenues									437,887	380,418	360,776
Operating segments | West segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues									228,055	219,743	211,788
Operating segments | West segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									89,566	82,406	80,003
Operating segments | West segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues									90,824	76,147	73,180
Operating segments | West segment | Racing
Disaggregation of Revenue [Line Items]
Revenues									580	2,340	2,331
Operating segments | West segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									10,459	26,060	15,997
Operating segments | West segment | Other
Disaggregation of Revenue [Line Items]
Revenues									18,403	16,605	16,260
Operating segments | Midwest segment
Disaggregation of Revenue [Line Items]
Revenues									823,717	782,206	751,904
Less: Promotional allowance										(47,173)	(47,632)
Revenues									823,717	735,033	704,272
Operating segments | Midwest segment | Gaming
Disaggregation of Revenue [Line Items]
Revenues									719,753	685,429	655,587
Operating segments | Midwest segment | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									57,886	58,414	58,370
Operating segments | Midwest segment | Hotel
Disaggregation of Revenue [Line Items]
Revenues									26,323	21,959	22,493
Operating segments | Midwest segment | Racing
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Operating segments | Midwest segment | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Operating segments | Midwest segment | Other
Disaggregation of Revenue [Line Items]
Revenues									19,755	16,404	15,454
Other
Disaggregation of Revenue [Line Items]
Revenues									40,449	52,228	41,825
Less: Promotional allowance										(535)	(134)
Revenues									40,449	51,693	41,691
Other | Gaming
Disaggregation of Revenue [Line Items]
Revenues									35	0	0
Other | Food and beverage
Disaggregation of Revenue [Line Items]
Revenues									1,084	1,052	1,313
Other | Hotel
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Other | Racing
Disaggregation of Revenue [Line Items]
Revenues									5,926	10,759	15,596
Other | Reimbursable management costs
Disaggregation of Revenue [Line Items]
Revenues									0	0	0
Other | Other
Disaggregation of Revenue [Line Items]
Revenues									$ 33,404	$ 40,417	$ 24,916