REVENUE RECOGNITION - Impact of Adoption on Income Statement (Details) - USD ($) $ / shares in Units, $ 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
Revenues
Gross revenues									$ 240,315	$ 279,252	$ 264,144
Less promotional allowances										(48,526)	(47,112)
Net revenues	$ 59,779	$ 64,359	$ 59,909	$ 56,268	$ 56,056	$ 63,027	$ 58,229	$ 53,414	240,315	230,726	217,032
Operating expenses
Selling, general and administrative									65,802	62,719	57,730
Depreciation and amortization									14,617	15,132	14,835
Loss on disposition of assets									12	4	677
Total operating expenses	50,718	50,493	48,567	47,711	47,919	49,777	46,676	45,688	197,489	190,060	178,484
Net income	$ 7,259	$ 10,859	$ 9,239	$ 6,741	$ 4,397	$ 9,030	$ 7,239	$ 4,872	$ 34,098	$ 25,538	$ 24,574
Basic (in dollars per share)	$ 0.40	$ 0.61	$ 0.52	$ 0.38	$ 0.25	$ 0.51	$ 0.41	$ 0.28	$ 1.91	$ 1.45	$ 1.42
Diluted (in dollars per share)	$ 0.39	$ 0.58	$ 0.50	$ 0.36	$ 0.23	$ 0.49	$ 0.40	$ 0.27	$ 1.83	$ 1.39	$ 1.39
Casino
Revenues
Gross revenues									$ 125,844	$ 178,585	$ 168,861
Operating expenses
Operating expenses									43,791	73,017	69,529
Food and beverage
Revenues
Gross revenues									71,212	63,416	60,269
Operating expenses
Operating expenses									54,002	25,727	24,627
Hotel
Revenues
Gross revenues									30,497	24,784	23,374
Operating expenses
Operating expenses									13,059	9,320	7,231
Other
Revenues
Gross revenues									12,762	12,467	11,640
Operating expenses
Operating expenses									6,206	$ 4,141	$ 3,855
ASC 606 Changes
Revenues
Gross revenues									49,907
Less promotional allowances									(50,843)
Net revenues									(936)
Operating expenses
Total operating expenses									(936)
ASC 606 Changes | Casino
Revenues
Gross revenues									59,522
Operating expenses
Operating expenses									33,174
ASC 606 Changes | Food and beverage
Revenues
Gross revenues									(5,600)
Operating expenses
Operating expenses									(28,550)
ASC 606 Changes | Hotel
Revenues
Gross revenues									(4,158)
Operating expenses
Operating expenses									(3,428)
ASC 606 Changes | Other
Revenues
Gross revenues									143
Operating expenses
Operating expenses									(2,132)
Pre ASC 606 Adoption
Revenues
Gross revenues									290,222
Less promotional allowances									(50,843)
Net revenues									239,379
Operating expenses
Selling, general and administrative									65,802
Depreciation and amortization									14,617
Loss on disposition of assets									12
Total operating expenses									196,553
Net income									$ 34,098
Basic (in dollars per share)									$ 1.91
Diluted (in dollars per share)									$ 1.83
Pre ASC 606 Adoption | Casino
Revenues
Gross revenues									$ 185,366
Operating expenses
Operating expenses									76,965
Pre ASC 606 Adoption | Food and beverage
Revenues
Gross revenues									65,612
Operating expenses
Operating expenses									25,452
Pre ASC 606 Adoption | Hotel
Revenues
Gross revenues									26,339
Operating expenses
Operating expenses									9,631
Pre ASC 606 Adoption | Other
Revenues
Gross revenues									12,905
Operating expenses
Operating expenses									$ 4,074