Condensed Consolidating Financial Statements (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Repayments of Long-term Debt	$ 400,000	$ 0
Net cash provided by (used in) operating activities:	(627,577)	(492,373)
Purchases of AFS securities	(100)	(45,158)
Maturities of and payments received on AFS securities	49,013	55,615
Principal payments on mortgage loans held for investment, net	13,451	24,340
Capital expenditures	(70,927)	(86,926)
Payments made for business acquisitions, net of cash acquired	94,230	20,927
Loans made to franchisees	(18,251)	(22,114)
Repayments from franchisees	29,637	15,883
Intercompany payments/investments in subsidiaries
Other, net	10,685	15,255
Net cash provided by (used in) investing activities	(80,722)	(64,032)
Customer banking deposits, net	(316,269)	(275,800)
Dividends paid	(109,871)	(109,324)
Proceeds from exercise of stock options	14,477	24,536
Intercompany borrowings (repayments)
Other, net	(33,639)	(31,948)
Net cash used in financing activities	(845,302)	(392,536)
Effects of exchange rates on cash	(4,216)	(7,871)
Net decrease in cash and cash equivalents	(1,557,817)	(956,812)
Cash & cash equivalents	627,490	790,772
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of Long-term Debt
Net cash provided by (used in) operating activities:		799
Purchases of AFS securities
Maturities of and payments received on AFS securities
Principal payments on mortgage loans held for investment, net
Capital expenditures
Payments made for business acquisitions, net of cash acquired
Loans made to franchisees
Repayments from franchisees
Intercompany payments/investments in subsidiaries
Other, net
Net cash provided by (used in) investing activities
Customer banking deposits, net
Dividends paid	(109,871)	(109,324)
Proceeds from exercise of stock options	14,477	24,536
Intercompany borrowings (repayments)	105,641	89,318
Other, net	(10,247)	(5,329)
Net cash used in financing activities		(799)
Effects of exchange rates on cash
Net decrease in cash and cash equivalents
Cash & cash equivalents
Block Financial Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of Long-term Debt	400,000
Net cash provided by (used in) operating activities:	55,612	46,969
Purchases of AFS securities		(45,158)
Maturities of and payments received on AFS securities	49,013	55,615
Principal payments on mortgage loans held for investment, net	13,451	24,340
Capital expenditures	(119)	(57)
Payments made for business acquisitions, net of cash acquired
Loans made to franchisees	(18,180)	(22,114)
Repayments from franchisees	29,404	15,883
Intercompany payments/investments in subsidiaries	400,000	23,036
Other, net	4,372	11,368
Net cash provided by (used in) investing activities	477,941	62,913
Customer banking deposits, net	(317,095)	(278,077)
Dividends paid
Proceeds from exercise of stock options
Intercompany borrowings (repayments)	3,390
Other, net
Net cash used in financing activities	(713,705)	(278,077)
Effects of exchange rates on cash
Net decrease in cash and cash equivalents	(180,152)	(168,195)
Cash & cash equivalents	432,224	389,915
Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of Long-term Debt
Net cash provided by (used in) operating activities:	(683,189)	(540,141)
Purchases of AFS securities	(100)
Maturities of and payments received on AFS securities
Principal payments on mortgage loans held for investment, net
Capital expenditures	(70,808)	(86,869)
Payments made for business acquisitions, net of cash acquired	94,230	20,927
Loans made to franchisees	(71)
Repayments from franchisees	233
Intercompany payments/investments in subsidiaries	(109,031)	(89,318)
Other, net	6,313	3,887
Net cash provided by (used in) investing activities	(267,694)	(193,227)
Customer banking deposits, net
Dividends paid
Proceeds from exercise of stock options
Intercompany borrowings (repayments)	(400,000)	(23,036)
Other, net	(23,392)	(26,619)
Net cash used in financing activities	(423,392)	(49,655)
Effects of exchange rates on cash	(4,216)	(7,871)
Net decrease in cash and cash equivalents	(1,378,491)	(790,894)
Cash & cash equivalents	195,540	401,303
Intersegment Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of Long-term Debt
Net cash provided by (used in) operating activities:
Purchases of AFS securities
Maturities of and payments received on AFS securities
Principal payments on mortgage loans held for investment, net
Capital expenditures
Payments made for business acquisitions, net of cash acquired
Loans made to franchisees
Repayments from franchisees
Intercompany payments/investments in subsidiaries	(290,969)	66,282
Other, net
Net cash provided by (used in) investing activities	(290,969)	66,282
Customer banking deposits, net	826	2,277
Dividends paid
Proceeds from exercise of stock options
Intercompany borrowings (repayments)	290,969	(66,282)
Other, net
Net cash used in financing activities	291,795	(64,005)
Effects of exchange rates on cash
Net decrease in cash and cash equivalents	826	2,277
Cash & cash equivalents	$ (274)	$ (446)