Estimated Cost of Promotional Allowances (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Promotional Allowance	$ 0	$ 1,052,821	$ 0	$ 3,117,506
Food and beverage [Member]
Promotional Allowance	992,595	1,012,407	2,863,087	2,991,976
Other [Member]
Promotional Allowance	$ 40,995	$ 40,414	$ 122,552	$ 125,530