Segment Reporting (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Segment Reporting Information [Line Items]
Net revenues	$ 14,564,377	$ 14,482,729	$ 43,798,999	$ 45,504,839
Casino and food and beverage expense	7,688,674	8,370,976	23,478,962	26,596,920
Marketing, administrative and corporate expense	6,026,838	4,812,850	17,526,312	14,860,789
Facility and other expenses	487,239	481,734	1,486,619	1,413,266
Depreciation and amortization	112,537	198,522	357,193	761,111
Operating income (loss)	249,089	618,339	984,269	1,866,980
Washington
Segment Reporting Information [Line Items]
Net revenues	14,564,377	13,314,264	42,970,445	40,263,535
Casino and food and beverage expense	7,688,674	7,239,816	22,540,802	21,942,455
Marketing, administrative and corporate expense	4,395,723	4,099,481	13,133,387	12,582,737
Facility and other expenses	487,239	458,938	1,469,896	1,345,352
Depreciation and amortization	107,065	119,007	339,437	465,886
Operating income (loss)	1,885,675	1,396,947	5,486,149	3,921,445
South Dakota
Segment Reporting Information [Line Items]
Net revenues	0	1,168,465	828,554	5,241,304
Casino and food and beverage expense	0	1,131,160	938,160	4,654,465
Marketing, administrative and corporate expense	0	134,999	131,280	368,321
Facility and other expenses	0	22,796	16,723	67,914
Depreciation and amortization	0	72,980	0	275,345
Operating income (loss)	0	(193,703)	(199,917)	(124,854)
Corporate
Segment Reporting Information [Line Items]
Net revenues	0	0	0	0
Casino and food and beverage expense	0	0	0	0
Marketing, administrative and corporate expense	1,631,115	578,370	4,261,645	1,909,731
Facility and other expenses	0	0	0	0
Depreciation and amortization	5,472	6,535	17,756	19,880
Operating income (loss)	$ (1,636,586)	$ (584,905)	$ (4,301,963)	$ (1,929,611)