Note 18 - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Feb. 29, 2016	May. 31, 2015
Parent Company [Member]
CURRENT ASSETS:
Cash and cash equivalents	$ 2,680	$ 7,080
Trade accounts receivable, net of allowance for doubtful accounts of $1,978 and $1,669 at February 29, 2016 and May 31, 2015, respectively	26,717	30,442
Intercompany receivable	81,485	68,815
Inventories, net	21,779	18,361
Deferred income tax assets, current portion	2,511	2,512
Prepaid expenses and other current assets	3,864	5,178
Total current assets	139,036	132,388
PROPERTY AND EQUIPMENT, net	39,582	38,915
INVESTMENT IN SUBSIDIARIES	209,211	220,412
GOODWILL	744,045	744,149
INTANGIBLE ASSETS, net	502,355	557,133
DEFERRED FINANCING COSTS, net	21,072	26,399
OTHER ASSETS	23,877	14,533
Total assets	1,679,178	1,733,929
CURRENT LIABILITIES:
Accounts payable	9,485	6,297
Intercompany payable	10,709	2,389
Accrued interest and interest rate swap liability	7,764	19,288
Accrued expenses and other current liabilities	9,098	13,758
Income taxes payable	30,050	30,061
Deferred revenue, current portion	1,540	1,498
Current portion of long-term debt, net of debt discounts	8,878	4,462
Total current liabilities	77,524	77,753
LONG-TERM DEBT, net of debt discounts	1,030,478	1,033,276
DEFERRED INCOME TAX LIABILITIES	203,432	223,232
OTHER LONG-TERM LIABILITIES	16,885	15,987
Total liabilities	1,328,319	1,350,248
Shareholders' equity of Immucor, Inc.	$ 350,859	383,681
Equity of noncontrolling interest (Note 4)
Total equity	$ 350,859
Total liabilities and equity	1,679,178	1,733,929
Shareholders' equity of Immucor, Inc.:
Shareholders' equity of Immucor, Inc.	350,859	383,681
Total liabilities and equity	1,679,178	1,733,929
Guarantor Subsidiaries [Member]
CURRENT ASSETS:
Cash and cash equivalents	(518)	(263)
Trade accounts receivable, net of allowance for doubtful accounts of $1,978 and $1,669 at February 29, 2016 and May 31, 2015, respectively	6,463	6,014
Intercompany receivable	23,737	24,201
Inventories, net	15,917	13,706
Deferred income tax assets, current portion	2,254	2,253
Prepaid expenses and other current assets	419	426
Total current assets	48,272	46,337
PROPERTY AND EQUIPMENT, net	12,677	13,849
INVESTMENT IN SUBSIDIARIES	5,020	5,021
GOODWILL	47,985	47,640
INTANGIBLE ASSETS, net	$ 56,081	$ 59,164
DEFERRED FINANCING COSTS, net
OTHER ASSETS	$ 234	$ 310
Total assets	170,269	172,321
CURRENT LIABILITIES:
Accounts payable	3,641	2,604
Intercompany payable	$ 98,863	$ 91,547
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities	$ 5,013	$ 5,131
Income taxes payable	$ (30,092)	(30,074)
Deferred revenue, current portion		7
Current portion of long-term debt, net of debt discounts		7
Total current liabilities	$ 77,425	$ 69,222
LONG-TERM DEBT, net of debt discounts
DEFERRED INCOME TAX LIABILITIES	$ (194)	$ 3,639
OTHER LONG-TERM LIABILITIES	12,583	11,908
Total liabilities	89,814	84,769
Shareholders' equity of Immucor, Inc.	$ 80,455	87,552
Equity of noncontrolling interest (Note 4)
Total equity	$ 80,455
Total liabilities and equity	170,269	172,321
Shareholders' equity of Immucor, Inc.:
Shareholders' equity of Immucor, Inc.	80,455	87,552
Total liabilities and equity	170,269	172,321
Non-Guarantor Subsidiaries [Member]
CURRENT ASSETS:
Cash and cash equivalents	10,028	11,546
Trade accounts receivable, net of allowance for doubtful accounts of $1,978 and $1,669 at February 29, 2016 and May 31, 2015, respectively	26,790	31,218
Intercompany receivable	14,788	8,861
Inventories, net	12,086	11,830
Deferred income tax assets, current portion	508	375
Prepaid expenses and other current assets	5,534	5,557
Total current assets	69,734	69,387
PROPERTY AND EQUIPMENT, net	20,529	20,810
INVESTMENT IN SUBSIDIARIES	3,019	3,019
GOODWILL	48,811	50,469
INTANGIBLE ASSETS, net	$ 50,396	$ 33,997
DEFERRED FINANCING COSTS, net
OTHER ASSETS	$ 444	$ 342
Total assets	192,933	178,024
CURRENT LIABILITIES:
Accounts payable	4,429	4,965
Intercompany payable	$ 10,438	$ 7,941
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities	$ 5,392	$ 7,319
Income taxes payable	3,150	3,509
Deferred revenue, current portion	$ 1,116	$ 1,198
Current portion of long-term debt, net of debt discounts
Total current liabilities	$ 24,525	$ 24,932
LONG-TERM DEBT, net of debt discounts
DEFERRED INCOME TAX LIABILITIES	$ 16,113	$ 9,616
OTHER LONG-TERM LIABILITIES	8,547	1,317
Total liabilities	49,185	35,865
Shareholders' equity of Immucor, Inc.	137,985	142,159
Equity of noncontrolling interest (Note 4)	5,763
Total equity	143,748
Total liabilities and equity	192,933	178,024
Shareholders' equity of Immucor, Inc.:
Shareholders' equity of Immucor, Inc.	137,985	142,159
Total liabilities and equity	$ 192,933	$ 178,024
Consolidation, Eliminations [Member]
CURRENT ASSETS:
Cash and cash equivalents
Trade accounts receivable, net of allowance for doubtful accounts of $1,978 and $1,669 at February 29, 2016 and May 31, 2015, respectively
Intercompany receivable	$ (120,010)	$ (101,877)
Inventories, net	(1,938)	(2,050)
Deferred income tax assets, current portion	$ 748	$ 791
Prepaid expenses and other current assets
Total current assets	$ (121,200)	$ (103,136)
PROPERTY AND EQUIPMENT, net
INVESTMENT IN SUBSIDIARIES	$ (217,250)	$ (228,452)
GOODWILL
INTANGIBLE ASSETS, net
DEFERRED FINANCING COSTS, net
OTHER ASSETS	$ (7,250)
Total assets	$ (345,700)	$ (331,588)
CURRENT LIABILITIES:
Accounts payable
Intercompany payable	$ (120,010)	$ (101,877)
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities
Income taxes payable
Deferred revenue, current portion
Current portion of long-term debt, net of debt discounts
Total current liabilities	$ (120,010)	$ (101,877)
LONG-TERM DEBT, net of debt discounts
DEFERRED INCOME TAX LIABILITIES
OTHER LONG-TERM LIABILITIES	$ (7,250)
Total liabilities	(127,260)	$ (101,877)
Shareholders' equity of Immucor, Inc.	$ (218,440)	(229,711)
Equity of noncontrolling interest (Note 4)
Total equity	$ (218,440)
Total liabilities and equity	(345,700)	(331,588)
Shareholders' equity of Immucor, Inc.:
Shareholders' equity of Immucor, Inc.	(218,440)	(229,711)
Total liabilities and equity	(345,700)	(331,588)
Cash and cash equivalents	12,190	18,363
Trade accounts receivable, net of allowance for doubtful accounts of $1,978 and $1,669 at February 29, 2016 and May 31, 2015, respectively	$ 59,970	$ 67,674
Intercompany receivable
Inventories, net	$ 47,844	$ 41,847
Deferred income tax assets, current portion	6,021	5,931
Prepaid expenses and other current assets	9,817	11,161
Total current assets	135,842	144,976
PROPERTY AND EQUIPMENT, net	$ 72,788	$ 73,574
INVESTMENT IN SUBSIDIARIES
GOODWILL	$ 840,841	$ 842,258
INTANGIBLE ASSETS, net	608,832	650,294
DEFERRED FINANCING COSTS, net	21,072	26,399
OTHER ASSETS	17,305	15,185
Total assets	1,696,680	1,752,686
Accounts payable	$ 17,555	$ 13,866
Intercompany payable
Accrued interest and interest rate swap liability	$ 7,764	$ 19,288
Accrued expenses and other current liabilities	19,503	26,208
Income taxes payable	3,108	3,496
Deferred revenue, current portion	2,656	2,703
Current portion of long-term debt, net of debt discounts	8,878	4,469
Total current liabilities	59,464	70,030
LONG-TERM DEBT, net of debt discounts	1,030,478	1,033,276
DEFERRED INCOME TAX LIABILITIES	219,351	236,487
OTHER LONG-TERM LIABILITIES	30,765	29,212
Total liabilities	1,340,058	1,369,005
Shareholders' equity of Immucor, Inc.	350,859	$ 383,681
Equity of noncontrolling interest (Note 4)	5,763
Total equity	356,622	$ 383,681
Total liabilities and equity	1,696,680	1,752,686
Shareholders' equity of Immucor, Inc.	350,859	383,681
Total liabilities and equity	$ 1,696,680	$ 1,752,686