Note 17 - Condensed Consolidating Financial Information of Guarantor Subsidiaries (Details) - Condensed Consolidating Cash Flow Information (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Nov. 30, 2014	Nov. 30, 2013	Aug. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 15,013	$ 13,045
Net cash provided by (used in) investing activities	(18,599)	(3,195)
Net cash provided by ( used in) financing activities	(3,328)	(3,678)
Effect of exchange rate changes on cash and cash equivalents	(1,602)	663
(Decrease) increase in cash and cash equivalents	(8,516)	6,835
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	23,621	29,388	15,105
CASH AND CASH EQUIVALENTS AT END OF PERIOD	15,105	36,223	15,105
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(396)	(797)
Net cash provided by ( used in) financing activities	324	785
Effect of exchange rate changes on cash and cash equivalents	72	12
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	12,001	8,013
Net cash provided by (used in) investing activities	(9,770)	4,084
Net cash provided by ( used in) financing activities	(3,317)	(3,647)
Effect of exchange rate changes on cash and cash equivalents	(137)	(34)
(Decrease) increase in cash and cash equivalents	(1,223)	8,416
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	4,863	6,971	3,675
CASH AND CASH EQUIVALENTS AT END OF PERIOD	3,675	15,387	3,675
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	1,805	(2,735)
Net cash provided by (used in) investing activities	(1,435)	(1,169)
Net cash provided by ( used in) financing activities	(12)	(31)
(Decrease) increase in cash and cash equivalents	358	(3,935)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	(409)	4,107	(87)
CASH AND CASH EQUIVALENTS AT END OF PERIOD	(87)	172	(87)
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	1,603	8,564
Net cash provided by (used in) investing activities	(7,394)	(6,110)
Net cash provided by ( used in) financing activities	(323)	(785)
Effect of exchange rate changes on cash and cash equivalents	(1,537)	685
(Decrease) increase in cash and cash equivalents	(7,651)	2,354
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	19,167	18,310	11,517
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 11,517	$ 20,664	$ 11,517