Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2010
Cash flows from operating activities:
Net income	$ 13,727	$ 12,642	$ 18,446
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred taxes	744	1,351	(1,084)
Depreciation and amortization	5,922	3,563	3,105
Amortization of debt issue costs	508	197	156
Impairment of property and equipment	304	0	0
Loss (gain) on disposition of property and equipment	(7)	51	(4)
Stock-based compensation	2,911	3,971	2,217
Excess tax benefit from equity instruments	(1,625)	(2,268)	(596)
Other	0	1	16
Changes in operating assets and liabilities:
Receivables	3,802	(6,791)	47
Inventories	2,637	158	(5,057)
Prepaid expenses and other	(467)	(456)	150
Deposits and other assets	(5)	0	0
Accounts payable	(2,489)	3,036	2,237
Accrued expenses	669	3,522	3,156
Income taxes receivable/payable	3,164	1,452	1,488
Other long-term liabilities	(925)	(1,028)	1,830
Net cash provided by operating activities	28,870	19,401	26,107
Cash flows from investing activities:
Purchase of businesses, net of cash acquired	(188,965)	0	0
Purchase of property and equipment	(2,732)	(3,997)	(2,942)
Proceeds from disposition of property and equipment	8	9	17
Purchase of available-for-sale securities	(6,979)	(10,415)	(25,761)
Proceeds from sale of available-for-sale securities	8,269	23,697	10,269
Net cash provided by (used in) investing activities	(190,399)	9,294	(18,417)
Cash flows from financing activities:
Proceeds from debt	190,000	0	0
Payments on debt	(48,000)	0	0
Dividends paid	(1,912)	(20,339)	(28,788)
Proceeds from stock options exercised	342	159	162
Purchase and retirement of common stock	(1,867)	(3,004)	(10)
Excess tax benefit from equity instruments	1,625	2,268	596
Payments for debt issue costs	(9,166)	0	(530)
Contingent consideration settlement payments	(433)	0	0
Net cash provided by (used in) financing activities	130,589	(20,916)	(28,570)
Increase (decrease) in cash and cash equivalents	(30,940)	7,779	(20,880)
Cash and cash equivalents, beginning of year	39,547	31,768	52,648
Cash and cash equivalents, end of year	$ 8,607	$ 39,547	$ 31,768