Note 22 - Condensed Consolidating Balance Sheets (Details) - USD ($)	May 31, 2016	May 31, 2015	May 31, 2014	May 31, 2013
Parent Company [Member] | Reportable Legal Entities [Member]
Current Assets:
Cash and cash equivalents	$ 4,058,000	$ 7,080,000	$ 4,863,000	$ 6,971,000
Accounts receivable, net	28,314,000	30,442,000
Intercompany receivable	98,375,000	68,815,000
Inventories, net	19,853,000	18,361,000
Prepaid expenses and other current assets	3,381,000	5,178,000
Total current assets	153,981,000	129,876,000
Property and equipment, net	39,724,000	38,915,000
Investment in subsidiaries	211,451,000	220,412,000
Goodwill	744,044,000	744,149,000
Other intangible assets, net	489,871,000	557,133,000
Other assets	30,346,000	14,533,000
Total assets	1,669,417,000	1,705,018,000
Current Liabilities:
Accounts payable	10,622,000	6,297,000
Intercompany payable	18,293,000	2,389,000
Accrued interest and interest rate swap liability	18,869,000	19,288,000
Accrued expenses and other current liabilities	10,700,000	13,758,000
Income taxes payable	30,190,000	30,061,000
Deferred revenue, current portion	1,785,000	1,498,000
Current portion of long-term debt	6,634,000	6,633,000
Total current liabilities	97,093,000	79,924,000
Long-term debt, excluding current portion	1,007,888,000	1,004,706,000
Deferred income tax liabilities	201,489,000	220,720,000
Other long-term liabilities	22,724,000	15,987,000
Total liabilities	1,329,194,000	1,321,337,000
Equity:
Shareholders' equity of Immucor, Inc.	340,223,000	383,681,000
Noncontrolling interest
Total equity	340,223,000
Total liabilities and equity	1,669,417,000	1,705,018,000
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Current Assets:
Cash and cash equivalents	(187,000)	(263,000)	(409,000)	4,107,000
Accounts receivable, net	5,866,000	6,014,000
Intercompany receivable	26,311,000	24,201,000
Inventories, net	17,321,000	13,706,000
Prepaid expenses and other current assets	449,000	426,000
Total current assets	49,760,000	44,084,000
Property and equipment, net	14,713,000	13,849,000
Investment in subsidiaries	20,033,000	5,021,000
Goodwill	62,771,000	47,640,000
Other intangible assets, net	92,500,000	59,164,000
Other assets	274,000	310,000
Total assets	240,051,000	170,068,000
Current Liabilities:
Accounts payable	5,517,000	2,604,000
Intercompany payable	117,516,000	91,547,000
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities	5,230,000	5,131,000
Income taxes payable	(29,838,000)	(30,074,000)
Deferred revenue, current portion		7,000
Current portion of long-term debt	172,000	7,000
Total current liabilities	98,597,000	69,222,000
Long-term debt, excluding current portion	60,000
Deferred income tax liabilities	7,070,000	1,386,000
Other long-term liabilities	43,099,000	11,908,000
Total liabilities	148,826,000	82,516,000
Equity:
Shareholders' equity of Immucor, Inc.	91,225,000	87,552,000
Noncontrolling interest
Total equity	91,225,000
Total liabilities and equity	240,051,000	170,068,000
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Current Assets:
Cash and cash equivalents	6,356,000	11,546,000	19,167,000	18,310,000
Accounts receivable, net	27,863,000	31,218,000
Intercompany receivable	24,710,000	8,861,000
Inventories, net	11,415,000	11,830,000
Prepaid expenses and other current assets	4,649,000	5,557,000
Total current assets	74,993,000	69,012,000
Property and equipment, net	20,934,000	20,810,000
Investment in subsidiaries	3,019,000	3,019,000
Goodwill	50,103,000	50,469,000
Other intangible assets, net	31,906,000	33,997,000
Other assets	360,000	324,000
Total assets	181,315,000	177,631,000
Current Liabilities:
Accounts payable	5,346,000	4,965,000
Intercompany payable	12,693,000	7,941,000
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities	6,075,000	7,243,000
Income taxes payable	2,233,000	3,509,000
Deferred revenue, current portion	1,079,000	1,198,000
Current portion of long-term debt
Total current liabilities	27,426,000	24,856,000
Long-term debt, excluding current portion
Deferred income tax liabilities	8,245,000	9,299,000
Other long-term liabilities	1,325,000	1,317,000
Total liabilities	36,996,000	35,472,000
Equity:
Shareholders' equity of Immucor, Inc.	144,319,000	142,159,000
Noncontrolling interest
Total equity	144,319,000
Total liabilities and equity	181,315,000	177,631,000
Immucor Inc and Subsidiaries [Member] | Reportable Legal Entities [Member]
Current Assets:
Cash and cash equivalents	10,227,000	18,363,000
Accounts receivable, net	62,043,000
Intercompany receivable	894,000
Inventories, net	46,894,000
Prepaid expenses and other current assets	8,479,000
Total current assets	128,537,000
Property and equipment, net	75,371,000
Investment in subsidiaries
Goodwill	856,918,000
Other intangible assets, net	614,277,000
Other assets	21,252,000
Total assets	1,696,355,000
Current Liabilities:
Accounts payable	21,485,000
Intercompany payable
Accrued interest and interest rate swap liability	18,869,000
Accrued expenses and other current liabilities	22,005,000
Income taxes payable	2,585,000
Deferred revenue, current portion	2,864,000
Current portion of long-term debt	6,806,000
Total current liabilities	74,614,000
Long-term debt, excluding current portion	1,007,948,000
Deferred income tax liabilities	216,150,000
Other long-term liabilities	57,420,000
Total liabilities	1,356,132,000
Equity:
Shareholders' equity of Immucor, Inc.	340,223,000
Noncontrolling interest
Total equity	340,223,000
Total liabilities and equity	1,696,355,000
Consolidation, Eliminations [Member]
Current Assets:
Cash and cash equivalents
Accounts receivable, net
Intercompany receivable	(148,502,000)	(101,877,000)
Inventories, net	(1,695,000)	(2,050,000)
Prepaid expenses and other current assets
Total current assets	(150,197,000)	(103,927,000)
Property and equipment, net
Investment in subsidiaries	(234,503,000)	(228,452,000)
Goodwill
Other intangible assets, net
Other assets	(9,728,000)
Total assets	(394,428,000)	(332,379,000)
Current Liabilities:
Accounts payable
Intercompany payable	(148,502,000)	(101,877,000)
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
Total current liabilities	(148,502,000)	(101,877,000)
Long-term debt, excluding current portion
Deferred income tax liabilities	(654,000)	(791,000)
Other long-term liabilities	(9,728,000)
Total liabilities	(158,884,000)	(102,668,000)
Equity:
Shareholders' equity of Immucor, Inc.	(235,544,000)	(229,711,000)
Noncontrolling interest
Total equity	(235,544,000)
Total liabilities and equity	(394,428,000)	(332,379,000)
VIE and VIE Eliminations [Member]
Current Assets:
Cash and cash equivalents	36,000
Accounts receivable, net
Intercompany receivable	(894,000)
Inventories, net
Prepaid expenses and other current assets
Total current assets	(858,000)
Property and equipment, net	644,000
Investment in subsidiaries
Goodwill	105,000
Other intangible assets, net	18,820,000
Other assets	(7,433,000)
Total assets	11,278,000
Current Liabilities:
Accounts payable	744,000
Intercompany payable
Accrued interest and interest rate swap liability
Accrued expenses and other current liabilities	4,000
Income taxes payable
Deferred revenue, current portion
Current portion of long-term debt
Total current liabilities	748,000
Long-term debt, excluding current portion
Deferred income tax liabilities	6,207,000
Other long-term liabilities
Total liabilities	6,955,000
Equity:
Shareholders' equity of Immucor, Inc.
Noncontrolling interest	4,323,000
Total equity	4,323,000
Total liabilities and equity	11,278,000
Cash and cash equivalents	10,263,000	18,363,000	23,621,000	29,388,000
Accounts receivable, net	62,043,000	67,674,000
Intercompany receivable
Inventories, net	46,894,000	41,847,000
Prepaid expenses and other current assets	8,479,000	11,161,000
Total current assets	127,679,000	139,045,000
Property and equipment, net	76,015,000	73,574,000
Investment in subsidiaries
Goodwill	857,023,000	842,258,000	851,563,000
Other intangible assets, net	633,097,000	650,294,000
Other assets	13,819,000	15,167,000
Total assets	1,707,633,000	1,720,338,000
Accounts payable	22,229,000	13,866,000
Intercompany payable
Accrued interest and interest rate swap liability	18,869,000	19,288,000
Accrued expenses and other current liabilities	22,009,000	26,132,000
Income taxes payable	2,585,000	3,496,000
Deferred revenue, current portion	2,864,000	2,703,000
Current portion of long-term debt	6,806,000	6,640,000
Total current liabilities	75,362,000	72,125,000
Long-term debt, excluding current portion	1,007,948,000	1,004,706,000
Deferred income tax liabilities	222,357,000	230,614,000
Other long-term liabilities	57,420,000	29,212,000
Total liabilities	1,363,087,000	1,336,657,000
Shareholders' equity of Immucor, Inc.	340,223,000	383,681,000
Noncontrolling interest	4,323,000
Total equity	344,546,000	383,681,000	$ 468,616,000	$ 644,706,000
Total liabilities and equity	$ 1,707,633,000	$ 1,720,338,000