REVENUE RECOGNITION - Impact of Adoption on Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Gross revenues									$ 249,166	$ 240,315	$ 279,252
Less promotional allowances											(48,526)
Net revenues	$ 62,080	$ 65,585	$ 62,761	$ 58,740	$ 59,779	$ 64,359	$ 59,909	$ 56,268	249,166	240,315	230,726
Operating expenses
Selling, general and administrative									69,312	65,802	62,719
Depreciation and amortization									14,875	14,617	15,132
Other operating items, net									3,112	12	4
Total operating expenses	54,382	54,062	51,128	50,019	50,718	50,493	48,567	47,711	209,591	197,489	190,060
Net income	$ 6,196	$ 9,326	$ 9,279	$ 7,015	$ 7,259	$ 10,859	$ 9,239	$ 6,741	$ 31,816	$ 34,098	$ 25,538
Basic (in dollars per share)	$ 0.34	$ 0.52	$ 0.52	$ 0.39	$ 0.40	$ 0.61	$ 0.52	$ 0.38	$ 1.77	$ 1.91	$ 1.45
Diluted (in dollars per share)	$ 0.33	$ 0.50	$ 0.50	$ 0.38	$ 0.39	$ 0.58	$ 0.50	$ 0.36	$ 1.70	$ 1.83	$ 1.39
Casino
Revenues
Gross revenues									$ 128,010	$ 125,844	$ 178,585
Operating expenses
Operating expenses									45,259	43,791	73,017
Food and beverage
Revenues
Gross revenues									72,578	71,212	63,416
Operating expenses
Operating expenses									57,367	54,002	25,727
Hotel
Revenues
Gross revenues									35,222	30,497	24,784
Operating expenses
Operating expenses									13,123	13,059	9,320
Other
Revenues
Gross revenues									13,356	12,762	12,467
Operating expenses
Operating expenses									6,543	6,206	$ 4,141
ASC 606 Changes
Revenues
Gross revenues									57,872	49,907
Less promotional allowances									(58,885)	(50,843)
Net revenues									(1,013)	(936)
Operating expenses
Total operating expenses									(1,013)	(936)
ASC 606 Changes | Casino
Revenues
Gross revenues									71,306	59,522
Operating expenses
Operating expenses									29,563	33,174
ASC 606 Changes | Food and beverage
Revenues
Gross revenues									(5,335)	(5,600)
Operating expenses
Operating expenses									(22,670)	(28,550)
ASC 606 Changes | Hotel
Revenues
Gross revenues									(8,329)	(4,158)
Operating expenses
Operating expenses									(5,750)	(3,428)
ASC 606 Changes | Other
Revenues
Gross revenues									230	143
Operating expenses
Operating expenses									(2,156)	(2,132)
Pre ASC 606 Adoption
Revenues
Gross revenues									307,038	290,222
Less promotional allowances									(58,885)	(50,843)
Net revenues									248,153	239,379
Operating expenses
Selling, general and administrative									69,312	65,802
Depreciation and amortization									14,875	14,617
Other operating items, net									3,112	12
Total operating expenses									208,578	196,553
Net income									$ 31,816	$ 34,098
Basic (in dollars per share)									$ 1.77	$ 1.91
Diluted (in dollars per share)									$ 1.70	$ 1.83
Pre ASC 606 Adoption | Casino
Revenues
Gross revenues									$ 199,316	$ 185,366
Operating expenses
Operating expenses									74,822	76,965
Pre ASC 606 Adoption | Food and beverage
Revenues
Gross revenues									67,243	65,612
Operating expenses
Operating expenses									34,697	25,452
Pre ASC 606 Adoption | Hotel
Revenues
Gross revenues									26,893	26,339
Operating expenses
Operating expenses									7,373	9,631
Pre ASC 606 Adoption | Other
Revenues
Gross revenues									13,586	12,905
Operating expenses
Operating expenses									$ 4,387	$ 4,074