Condensed Consolidating Financial Statements (Balance Sheets) (Details) - USD ($) $ in Thousands	Jul. 31, 2015	Apr. 30, 2015	Jul. 31, 2014	Apr. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Cash & cash equivalents	$ 1,299,382	$ 2,007,190	$ 1,429,489	$ 2,185,307
Cash and cash equivalents - restricted	61,040	91,972	71,917
Receivables, net	103,194	167,964	122,315
Deferred Tax Assets, Net, Current	160,390	174,267	190,323
Prepaid expenses and other current assets	80,993	70,283	74,343
Investments in available-for-sale securities	406,360	439,625	403,774
Total current assets	2,111,359	2,951,301	2,292,161
Mortgage loans held for investment, net	230,130	239,338	259,732
Property and equipment, at cost less accumulated depreciation and amortization of $538,823, $468,372 and $518,797	297,321	311,387	314,531
Intangible assets, net	417,009	432,142	347,890
Goodwill	454,394	441,831	478,845	436,117
Deferred tax assets and income taxes receivable	11,377	13,461	46,953
Amounts due from affiliates	0	0	0
Other assets	111,101	125,960	150,707
Total assets	3,632,691	4,515,420	3,890,819
Customer deposits	476,732	744,241	482,975
Accounts payable and accrued expenses	116,855	231,322	127,912
Accrued salaries, wages and payroll taxes	33,447	144,744	30,996
Accrued income taxes	245,541	434,684	284,038
Current portion of long-term debt	799	790	400,705
Accounts payable and accrued expenses	316,880	322,508	357,293
Total current liabilities	1,190,254	1,878,289	1,683,919
Long-term debt	505,197	505,298	505,714
Deferred tax liabilities and reserves for uncertain tax positions	137,603	142,586	167,914
Deferred revenue and other noncurrent liabilities	130,210	156,298	136,072
Total liabilities	1,963,264	2,682,471	2,493,619
Stockholders’ equity	1,669,427	1,832,949	1,397,200
Total liabilities and stockholders' equity	3,632,691	4,515,420	3,890,819
Block Financial Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Cash & cash equivalents	286,165	478,077	405,512	612,376
Cash and cash equivalents - restricted	11,806	45,098	12,817
Receivables, net	77,539	80,332	86,968
Deferred Tax Assets, Net, Current	78,184	77,418	98,041
Prepaid expenses and other current assets	6,817	7,771	9,684
Investments in available-for-sale securities	404,221	434,924	403,674
Total current assets	864,732	1,123,620	1,016,696
Mortgage loans held for investment, net	230,130	239,338	259,732
Property and equipment, at cost less accumulated depreciation and amortization of $538,823, $468,372 and $518,797	210	218	209
Deferred tax assets and income taxes receivable	41,328	44,788	46,752
Amounts due from affiliates	131,889	134,094	322,339
Other assets	72,009	81,075	103,178
Total assets	1,340,298	1,623,133	1,748,906
Customer deposits	477,222	744,681	483,405
Accounts payable and accrued expenses	6,679	7,672	4,639
Accrued salaries, wages and payroll taxes	2,293	1,946	2,129
Accrued income taxes	49,240	49,529	30,944
Current portion of long-term debt			399,941
Accounts payable and accrued expenses	169,900	177,063	220,324
Total current liabilities	705,334	980,891	1,141,382
Long-term debt	497,964	497,893	497,682
Deferred tax liabilities and reserves for uncertain tax positions	26,737	25,696	57,242
Deferred revenue and other noncurrent liabilities	1,660	1,783	2,216
Amounts due to affiliates	21
Total liabilities	1,231,716	1,506,263	1,698,522
Stockholders’ equity	108,582	116,870	50,384
Total liabilities and stockholders' equity	1,340,298	1,623,133	1,748,906
Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash & cash equivalents	1,013,707	1,529,553	1,024,407	1,574,031
Cash and cash equivalents - restricted	49,234	46,874	59,100
Receivables, net	25,654	87,632	35,332
Deferred Tax Assets, Net, Current	82,206	96,849	92,265
Prepaid expenses and other current assets	74,176	62,512	64,659
Investments in available-for-sale securities	2,139	4,701	100
Total current assets	1,247,116	1,828,121	1,275,863
Property and equipment, at cost less accumulated depreciation and amortization of $538,823, $468,372 and $518,797	297,111	311,169	314,322
Intangible assets, net	417,009	432,142	347,890
Goodwill	454,394	441,831	478,845
Deferred tax assets and income taxes receivable			(3,194)
Investments in subsidiaries	108,582	116,870	50,384
Amounts due from affiliates	1,423	1,058	983
Other assets	39,092	44,885	47,529
Total assets	2,564,727	3,176,076	2,512,622
Accounts payable and accrued expenses	108,970	222,546	122,427
Accrued salaries, wages and payroll taxes	31,154	142,798	28,867
Accrued income taxes	196,301	385,155	253,094
Current portion of long-term debt	799	790	764
Accounts payable and accrued expenses	146,980	145,445	136,969
Total current liabilities	484,204	896,734	542,121
Long-term debt	7,233	7,405	8,032
Deferred tax liabilities and reserves for uncertain tax positions	140,817	148,217	105,277
Deferred revenue and other noncurrent liabilities	128,550	154,515	133,856
Amounts due to affiliates	544,813	597,528	938,917
Total liabilities	1,305,617	1,804,399	1,728,203
Stockholders’ equity	1,259,110	1,371,677	784,419
Total liabilities and stockholders' equity	2,564,727	3,176,076	2,512,622
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Receivables, net	1		15
Deferred Tax Assets, Net, Current			17
Total current assets	1		32
Deferred tax assets and income taxes receivable			3,395
Investments in subsidiaries	1,259,110	1,371,677	784,419
Amounts due from affiliates	412,924	463,434	616,578
Total assets	1,672,035	1,835,111	1,404,424
Accounts payable and accrued expenses	1,206	1,104	846
Total current liabilities	1,206	1,104	846
Deferred tax liabilities and reserves for uncertain tax positions			5,395
Amounts due to affiliates	1,402	1,058	983
Total liabilities	2,608	2,162	7,224
Stockholders’ equity	1,669,427	1,832,949	1,397,200
Total liabilities and stockholders' equity	1,672,035	1,835,111	1,404,424
Intersegment Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash & cash equivalents	(490)	(440)	(430)	$ (1,100)
Total current assets	(490)	(440)	(430)
Deferred tax assets and income taxes receivable	(29,951)	(31,327)
Investments in subsidiaries	(1,367,692)	(1,488,547)	(834,803)
Amounts due from affiliates	(546,236)	(598,586)	(939,900)
Total assets	(1,944,369)	(2,118,900)	(1,775,133)
Customer deposits	(490)	(440)	(430)
Total current liabilities	(490)	(440)	(430)
Deferred tax liabilities and reserves for uncertain tax positions	(29,951)	(31,327)
Amounts due to affiliates	(546,236)	(598,586)	(939,900)
Total liabilities	(576,677)	(630,353)	(940,330)
Stockholders’ equity	(1,367,692)	(1,488,547)	(834,803)
Total liabilities and stockholders' equity	$ (1,944,369)	$ (2,118,900)	$ (1,775,133)