Long-Term Incentive Awards (Details) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 29, 2017	Jul. 29, 2017	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Stock Based Compensation
Stock based compensation expense			$ 4,956,000	$ 3,392,000	$ 4,002,000
Fiscal 2018 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense			269,000
Fiscal 2018 LTIP | Performance based restricted stock units | 100% Vested
Stock Based Compensation
Vesting (as a percentage)	100.00%
Fiscal 2018 LTIP | Performance based restricted stock units | 50% Vested
Stock Based Compensation
Vesting (as a percentage)	50.00%
Fiscal 2018 LTIP | Performance based restricted stock units | 200% Vested
Stock Based Compensation
Vesting (as a percentage)	200.00%
Fiscal 2018 LTIP | Performance based restricted stock units | Maximum
Stock Based Compensation
Stock based compensation expense			2,660,000
Fiscal 2017 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense			159,000
Fiscal 2017 LTIP | Performance based restricted stock units | 100% Vested
Stock Based Compensation
Vesting (as a percentage)		100.00%
Fiscal 2017 LTIP | Performance based restricted stock units | 50% Vested
Stock Based Compensation
Vesting (as a percentage)		50.00%
Fiscal 2017 LTIP | Performance based restricted stock units | 200% Vested
Stock Based Compensation
Vesting (as a percentage)		200.00%
Fiscal 2017 LTIP | Performance based restricted stock units | Maximum
Stock Based Compensation
Stock based compensation expense			2,440,000
Fiscal 2016 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense			$ 0