Organization and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended									12 Months Ended
	Apr. 30, 2016 USD ($) Country Office $ / shares	Jan. 31, 2016 $ / shares	Oct. 31, 2015 $ / shares	Jul. 31, 2015 $ / shares	Apr. 30, 2015 USD ($) $ / shares		Jan. 31, 2015 $ / shares	Oct. 31, 2014 $ / shares	Jul. 31, 2014 $ / shares	Apr. 30, 2016 USD ($) Country Office $ / shares	Apr. 30, 2015 USD ($) $ / shares		Apr. 30, 2014 USD ($) $ / shares	Feb. 17, 2016 VEF / $
Organization And Summary Of Significant Accounting Policies [Line Items]
Number of offices | Office	150									150
Number of countries in which entity operates | Country	52									52
Investments in affiliated companies maximum	50.00%									50.00%
Dividends received from unconsolidated subsidiary										$ 2,373,000	$ 1,656,000		$ 2,120,000
Deferred revenue	$ 95,900,000				$ 40,500,000					95,900,000	40,500,000
Cash equivalents	117,500,000				260,600,000					117,500,000	260,600,000
Realized loss of other-than-temporary impairment										0	0		0
Marketable securities classified as available-for-sale investments	$ 0				$ 13,177,000	[1]				0	13,177,000	[1]
Payment of contingent consideration from acquisitions													15,000,000
Impairment of long-lived assets										0	0		0
Impairment of goodwill										0
Impairment of intangible assets										0	0
Performance related bonus expenses										187,100,000	166,700,000		146,100,000
(Decrease) increase in performance related bonus expenses										(600,000)	(300,000)		(700,000)
Performance related bonus after reduction in the previous year estimate										$ 186,500,000	166,400,000		145,400,000
Percentage that Actuarial gain or loss must exceed the greater of PBO or Market Value Plan Assets										10.00%
Foreign currency losses/(gains), after tax										$ 8,700,000	$ 1,600,000		$ (1,000,000)
Venezuelan foreign currency loss										$ 13,720,000
Diluted (loss) earnings per share | $ / shares	$ 0.10	$ (0.30)	$ 0.35	$ 0.46	$ 0.51		$ 0.46	$ 0.51	$ 0.29	$ 0.58	$ 1.76		$ 1.48
Not Designated as Hedging Instrument | Foreign Exchange Forward
Organization And Summary Of Significant Accounting Policies [Line Items]
Foreign currency gain/(loss)										$ (1,800,000)
Not Designated as Hedging Instrument | Foreign Exchange Forward | Other Accrued Liabilities
Organization And Summary Of Significant Accounting Policies [Line Items]
Derivative liabilities at fair value, net	$ 700,000									700,000
Derivative liabilities, gross	1,000,000									1,000,000
Derivative assets, gross	300,000									300,000
Not Designated as Hedging Instrument | Foreign Exchange Forward | Other Accrued Liabilities | Derivatives Purchased
Organization And Summary Of Significant Accounting Policies [Line Items]
Derivative notional amount	14,500,000									14,500,000
Not Designated as Hedging Instrument | Foreign Exchange Forward | Other Accrued Liabilities | Derivatives Sold
Organization And Summary Of Significant Accounting Policies [Line Items]
Derivative notional amount	44,300,000									$ 44,300,000
Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives										1 year
Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives										24 years
CSV of COLI Contracts
Organization And Summary Of Significant Accounting Policies [Line Items]
Gross CSV	175,700,000				$ 172,300,000					$ 175,700,000	$ 172,300,000
Outstanding policy loans	68,400,000				69,600,000					68,400,000	69,600,000
Receivable on insolvency of insurance companies	$ 55,900,000				$ 50,600,000					$ 55,900,000	50,600,000
Before Currency Devaluation
Organization And Summary Of Significant Accounting Policies [Line Items]
Foreign currency exchange rate, translation | VEF / $														6.3
After Currency Devaluation
Organization And Summary Of Significant Accounting Policies [Line Items]
Foreign currency exchange rate, translation | VEF / $														10.0
Devaluation Of Venezuelan Bolivar
Organization And Summary Of Significant Accounting Policies [Line Items]
Diluted (loss) earnings per share | $ / shares										$ (0.26)
Free-Floating Exchange Rate | After Currency Devaluation
Organization And Summary Of Significant Accounting Policies [Line Items]
Foreign currency exchange rate, translation | VEF / $														200
Rate used to calculate the impact of devaluation | After Currency Devaluation
Organization And Summary Of Significant Accounting Policies [Line Items]
Foreign currency exchange rate, translation | VEF / $														260
Accounting Standards Update 2015-17
Organization And Summary Of Significant Accounting Policies [Line Items]
Reclassification of deferred tax assets from current to non current											$ 3,800,000
Executive Capital Accumulation Plan
Organization And Summary Of Significant Accounting Policies [Line Items]
Deferred compensation arrangement vesting period										4 years
Software and Software Development Costs | Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life										3 years
Software and Software Development Costs | Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life										7 years
Other Capitalized Property Plant and Equipment | Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life										3 years
Other Capitalized Property Plant and Equipment | Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life										10 years

[1] The Company's financial assets measured at fair value on a recurring basis include trading securities classified as Level 1 and available-for-sale securities classified as Level 2. As of April 30, 2016 and 2015, the Company had no investments classified as Level 3.