REVENUE RECOGNITION - Impact of Adoption on Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Gross revenues	$ 59,909	$ 70,203	$ 116,177	$ 135,421
Less promotional allowances		(11,974)		(23,778)
Net revenues	59,909	58,229	116,177	111,643
Operating expenses:
Selling, general and administrative	16,152	15,080	31,337	29,719
Depreciation and amortization	3,738	3,769	7,430	7,675
Loss (gain) on disposition of assets	4	(14)	4	4
Total operating expenses	48,567	46,676	96,278	92,364
Net income	$ 9,239	$ 7,239	$ 15,980	$ 12,111
Basic (in dollars per share)	$ 0.52	$ 0.41	$ 0.90	$ 0.69
Diluted (in dollars per share)	$ 0.50	$ 0.40	$ 0.86	$ 0.67
Casino
Revenues:
Gross revenues	$ 31,142	$ 45,323	$ 61,087	$ 86,633
Operating expenses:
Operating expenses	10,856	18,060	21,552	35,740
Food and beverage
Revenues:
Gross revenues	17,541	15,562	34,479	31,052
Operating expenses:
Operating expenses	13,196	6,510	26,290	12,762
Hotel
Revenues:
Gross revenues	8,097	6,248	14,460	11,888
Operating expenses:
Operating expenses	3,056	2,249	6,555	4,457
Other
Revenues:
Gross revenues	3,129	3,070	6,151	5,848
Operating expenses:
Operating expenses	1,565	$ 1,022	3,110	$ 2,007
ASC 606 Changes | ASU 2014-09
Revenues:
Gross revenues	12,203		23,877
Less promotional allowances	(12,374)		(24,193)
Net revenues	(171)		(316)
Operating expenses:
Total operating expenses	(171)		(316)
ASC 606 Changes | ASU 2014-09 | Casino
Revenues:
Gross revenues	14,825		28,586
Operating expenses:
Operating expenses	8,049		16,331
ASC 606 Changes | ASU 2014-09 | Food and beverage
Revenues:
Gross revenues	(1,363)		(2,816)
Operating expenses:
Operating expenses	(6,944)		(13,867)
ASC 606 Changes | ASU 2014-09 | Hotel
Revenues:
Gross revenues	(1,279)		(1,937)
Operating expenses:
Operating expenses	(760)		(1,733)
ASC 606 Changes | ASU 2014-09 | Other
Revenues:
Gross revenues	20		44
Operating expenses:
Operating expenses	(516)		(1,047)
Pre ASC 606 Adoption | ASU 2014-09
Revenues:
Gross revenues	72,112		140,054
Less promotional allowances	(12,374)		(24,193)
Net revenues	59,738		115,861
Operating expenses:
Selling, general and administrative	16,152		31,337
Depreciation and amortization	3,738		7,430
Loss (gain) on disposition of assets	4		4
Total operating expenses	48,396		95,962
Net income	$ 9,239		$ 15,980
Basic (in dollars per share)	$ 0.52		$ 0.90
Diluted (in dollars per share)	$ 0.50		$ 0.86
Pre ASC 606 Adoption | ASU 2014-09 | Casino
Revenues:
Gross revenues	$ 45,967		$ 89,673
Operating expenses:
Operating expenses	18,905		37,883
Pre ASC 606 Adoption | ASU 2014-09 | Food and beverage
Revenues:
Gross revenues	16,178		31,663
Operating expenses:
Operating expenses	6,252		12,423
Pre ASC 606 Adoption | ASU 2014-09 | Hotel
Revenues:
Gross revenues	6,818		12,523
Operating expenses:
Operating expenses	2,296		4,822
Pre ASC 606 Adoption | ASU 2014-09 | Other
Revenues:
Gross revenues	3,149		6,195
Operating expenses:
Operating expenses	$ 1,049		$ 2,063