Deferred Compensation and Retirement Plans (Reconciliation of Fair Value of Plan Assets) (Detail) - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, end of year	$ 24,867	$ 24,867
Current liability	17,946	17,946	$ 18,014
Non-current liability	216,113	216,113	173,432
Total liability	234,059	234,059	191,446
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, at acquisition date		5,262	4,424	$ 4,536
Interest cost		167	154	137
Actuarial loss		122	1,001	92
Benefits paid		(332)	(317)	(341)
Benefit obligation, end of year	5,219	5,219	5,262	$ 4,424
Total liability	5,219	5,219	$ 5,262
Pension Plans, Defined Benefit | Legacy Hay Group
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, at acquisition date	32,795
Interest cost	554
Actuarial loss	2,438
Benefits paid	(595)
Benefit obligation, end of year	35,192	35,192
Fair value of plan assets at acquisition date	25,540
Actual return on plan assets	(78)
Benefits paid	(595)
Fair value of plan assets, end of year	24,867	24,867
Funded status and balance, end of year	(10,325)	(10,325)
Non-current liability	10,325	10,325
Total liability	$ 10,325	$ 10,325
Plan assets weighted average allocation	100.00%	100.00%
Pension Plans, Defined Benefit | Legacy Hay Group | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets weighted average allocation	63.90%	63.90%
Pension Plans, Defined Benefit | Legacy Hay Group | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets weighted average allocation	30.80%	30.80%
Pension Plans, Defined Benefit | Legacy Hay Group | Other Debt Obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets weighted average allocation	5.30%	5.30%
Supplemental Pension Benefits | Legacy Hay Group
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, at acquisition date	$ 6,284
Interest cost	58
Actuarial loss	113
Settlements	(4,799)
Benefits paid	(47)
Benefit obligation, end of year	1,609	$ 1,609
Funded status and balance, end of year	(1,609)	(1,609)
Current liability	110	110
Non-current liability	1,499	1,499
Total liability	1,609	1,609
Medical And Life Insurance | Legacy Hay Group
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, at acquisition date	12,322
Service cost	62
Interest cost	208
Actuarial loss	816
Benefits paid	(402)
Benefit obligation, end of year	13,006	13,006
Funded status and balance, end of year	(13,006)	(13,006)
Current liability	673	673
Non-current liability	12,333	12,333
Total liability	$ 13,006	$ 13,006