Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Cash flows from operating activities
Net income	$ 24,650	$ 15,991	$ 22,575
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	32,474	33,286	28,429
Deferred income taxes	240	(1,745)	(621)
Share-based compensation expense	6,514	6,579	6,261
Charges associated with the exit of foreign operations	0	2,516	0
Fair value adjustments to contingent consideration	(2,066)	(5,382)	(3,937)
Other	(1,052)	1,647	617
Changes in operating assets and liabilities, net of effect of acquisitions
Accounts receivable	(4,999)	3,982	(23,857)
Inventories	1,595	388	1,203
Prepaid expenses and other current assets	(1,128)	(288)	(4,059)
Other assets	(684)	(821)	36
Accounts payable	254	(6,571)	6,125
Accrued expenses and other liabilities	10,187	2,006	4,532
Income taxes payable	2,139	(1,748)	(431)
Net cash provided by operating activities	68,124	49,840	36,873
Cash flows from investing activities
Purchase of property, plant and equipment	(14,864)	(15,104)	(16,871)
Purchase of intangible assets	(1,315)	(866)	(708)
Acquisition of businesses, net of cash acquired	(1,743)	(34,677)	(21,924)
Proceeds from sale of equipment	1,170	996	1,498
Net cash used in investing activities	(16,752)	(49,651)	(38,005)
Cash flows from financing activities
Repayment of capital lease obligations	(7,870)	(8,653)	(8,139)
Proceeds from borrowings of long-term debt	2,737	2,232	0
Repayment of long-term debt	(17,580)	(11,457)	(8,830)
Proceeds from revolver	55,800	110,300	102,880
Repayments of revolver	(69,600)	(86,800)	(81,300)
Payment of contingent consideration for business acquisitions	(3,147)	(3,213)	(1,678)
Taxes paid related to net share settlement of equity awards	(1,091)	(1,481)	(1,007)
Excess tax benefit from share-based payment compensation	(170)	388	340
Proceeds from the exercise of stock options	543	750	996
Net cash (used in) provided by financing activities	(40,378)	2,066	3,262
Effect of exchange rate changes on cash and cash equivalents	(361)	(1,720)	88
Net change in cash and cash equivalents	10,633	535	2,218
Cash and cash equivalents:
Beginning of period	10,555	10,020	7,802
End of period	21,188	10,555	10,020
Supplemental disclosure of cash paid
Interest	4,151	4,504	3,271
Income taxes	10,686	13,243	12,920
Noncash investing and financing
Equipment acquired through capital lease obligations	8,248	8,031	11,031
Issuance of notes payable and other debt obligations primarily related to acquisitions	$ 0	$ 20,480	$ 336